OK, well I'm over a year into this so it's a little late to get started, but I have pretty good notes and the machine is there as a record of what's going on.

I've decided to post here as I can keep it all in one thread -vs- the deal on Yahoo where it's all chopped up. I can post photos in line here as well. That will add to the context. Some photos later.

Here's where I am at.

First off what am I doing? I want to enter the insanely competitive world of kitchen gadgets to supplement my income. We live in "The OC" and things are just crazy expensive here. Everyone I know has something on the side going.

Why on earth would I do this? Well, I need a business partner and after 20 years of marriage I think my best bet is my wife. She likes to cook and loves kitchen gadgets. So, given that everything is competitive, this seems like a way to go. Maybe not the way, but a way.

2nd, these are relatively low tolerance products. +/- .005 is fine 90% of the time. Heck +/- .01 is OK some of the time. You don't have customers Micing a bottle openner.

3rd, design is important. I have a knack for design. I get 50 design ideas in my head every week. It's easy for me. Something I do well by nature. I also know that if I am successful that I will be ripped off, but I don't care. I'll just keep moving. My angle is to keep changing it up with short run products. If one of them goes hot, I'll license it to someone who does the high volume thing and keep going.

Ok that's the plan, we'll see how many ways I can screw that up.

The machine:

Given all that a three axis CNC machine seemed to be a natural fit. Part of this is about buying some U.S. made stuff so I decided to go with a Bridgeport.

So on about December 4th, 2003 I found an '82 J head on e-Bay and bought it. This was after visiting it at a more or less local machinery dealer and hour away. I'm convinced I paid too much. $3425.00. 48 inch bed, power feed on X, and a DRO, which I am not using at present. In good shape. Everything works pretty good on it. The power down feed needs some adjusting and there's something goofy in the vari speed, but it runs and is square. Not to bad for a Noobie I suppose.

It was delivered buy a nice guy named Gabriel. He hoisted it off his truck and rolled it into my Garage where it has been holding down the concreted since.

BTW - I have a Grizzly G1005 mill drill too. That was my first mill. I learned all about rigidity on that one. I also have a 7 x 12 mini lathe. Again, not too rigid. Turning AL is OK. Bronze starts to get interesting and steel is a real crap shoot anything better than +/- .005. On the Bridgy even I can eek out +/- .001 and I think I'll get better with time. So mass counts for a lot.

So now for the CNC stuff.

All the motor calc stuff went right over my head and I just did not have the patience for it then. I may yet be paying for that decision. But I winged it with some Reliance Micro 100 motors I found on e-Bay. 1/3 HP. 100 volts. The 100 V is going to be the issue.

I then got the Gecko drives and the Campbell / Sound Logic break out board. ( http://www.geckodrive.com/ http://www.campbelldesigns.com/ )

I have spun these motors succesfully under Mach2 and will go to Mach3 when I get back 'round to that. So I'll be writing about that real time.

One of the first things I decided to tackle was the electronics cabinet. I found a surplus cabinet at Youngs Surplus. ( http://www.youngssurplus.com/ ) It came with a bunch of relays and stuff in it too. Quite the find. It is big enough to house my mini tower clone PC, the DC power supply the relays, and the Geckos.

I did a whole DC power supply on my own. That's a whole story in and of it self. More on that later.

At this point the Bridgy has yet to be turned on. This 2200 pound paper weight was just a nice home to a bunch of electrical components. So how to power it up with my Dryer circuit? Well I did the whole research dance with phase converters, changing out the motor, rigging some crazy jack shaft thing, and the VFD. I bought a Leeson VFD in the end. I've never been happier with a power tool in my life as a result. The VFD not only takes care of the single phase to three phase problem it makes operating the machine a piece of cake. I can't wait to see how cool it can be with Mach2 controlling it.

Fortunately it powered up and ran good enough. I was afraid of some $1500 repair bill lurking in the J-Head. It was a little noisy, but once I got it greased and oiled it settled down. Before I go full production I need to take a deeper look in there.

Then I tackled the ball screws. I went with Rockford. I am happy. Rolled screws were fine given the products I want to make. Replacing them was a chore. My Dad helped me. It can be a one person job, but having someone there for safety is important. That table is really heavy.

We did discover that if the table is supported with some adjustable roller stands that it does not have to be taken all the way off. You can slide it to within about six inches of the end and avoid the whole hoist thing. We did the hoist thing on the first atempt.

I had purchased a shorter Y-screw to use for the Z-Drive and mistakenly installed that first. Then I ran the nut off the end of that and we had to redo the job and re load the other screw. Photo's of that eventually too. Not as bad as I thought.

So at that point I had power, computer, motors spinning, and X-Y screws installed. Yay!

It is now November 2004. Thanksgiving weekend. Now to mount the motors. I'm thinking now that I'll get the project in under a year.

Then a major set back. My z-Drive design was totally wrong. I was going to bolt this big ol' 1/2" AL plate to the tram bolts and mount everything on there. No go. WAY too much material and WAY too much flex as a result. I also started burning time making the bearing blocks.

This is when I started to learn about machine work for real. All of the sudden my world became about getting something, anything, within +/- .002. Well, several micrometers and several paper weights later, I can at least make the parts I need to.

So I am currently redesigning the z-Axis. Well that's all for today. Hopefully I'll get some pics and drawing and such posted here shortly.

Just added pics of the electrical cabinet and the big z-Drive plate of design number one.

Very interesting so far! A true labor of love. How much money invested so far? And then add to that a figure of your hours put in and attach a monetary value to that as well. I understand that you must enjoy the challenge, but when you add it all up, if you had just went out and bought a small used 3 axis knee style CNC machine, you would be making parts to sell right now. I have many projects laying around my house (and in the driveway) and to the regret of my wife, I think I will get them all done in a reasonable amount of time. It has not been so for years. But keep us posted. Have you looked at some of the designs already out there? You mentioned the aluminum plate. BPT (on the original Z drive EZTRAK design) used a 5/8 inch steel plate sandwiched between the head and the knuckel as a mounting surface for the drive components. That required longer "T" bolts to hold it all together. The latest design was made by ELROD and mounted to the front of the head. Very similar to an old BANDIT design I saw many years ago.

George W.

Money so far? Well, $3200 for the machine, $400 for the motors, $300 for the power supply after all my screw ups, uh.....misc stuff $1,000.00, break out board $100.00. Kurt vise $400.00. Cutting tools $500.00. I'm not done yet $2000.00. Wozt that? About $8K.

Yeah, after I value my time, I will probably be over the cost of many other options. But my time is only worth something if I can make money doing something else AND if I have the cash on hand to buy the machine. So it's a hard decision at that point. Do you try to save for the machine? I prefer to get going on the project then I have a drive to put the cash into that instead of the 18 other things I want. That's my oddness.

Heck a new CNC'd BP is $27K. Not that much really. I looked for used CNC machines. I probably should have looked a little longer and harder. Anyway.........here I am. The other objective here is to learn how to do this. I'm getting plenty of that.

Well, today was a bust. I'm working on the lower bearing block / mount for the z-Drive. I've decided to go Elrod style and grab the pads for the quill engagement lever and the quill speed. So it'll be a three point mount. I've been working for a week on the knuckle mounted bearing block. Today I over bored the bearing journal by a hair. I may be able to save it yet with a further over bore and a sleeve. Done that a couple times. :-) Also, I discovered that the top of the screw is going to hit the oil fitting up top. So I may need to back off the screw some. Which means a whole new part. Well, it'll take less time on the second go 'round. Could be worse.

In the attached pics you can see the block from the top and the bottom. Note the 5/8" allen bolt. I reduced the thickness of the cap on that and counter sunk it into the block.

A few more pics.

One is setting up the 7x12 to turn the ball screw.

The other is the VFD control panel.

Old School Power Supply Build Pics.

So the chaos on the dinning room table there is the operational circuit after I got it all bread boarded. Note the toroidial transformer on the right and the big 18,000 uf caps up towards the center. In between is my high voltage bread board. I just got a bunch of binding posts and mounted them to a panel. I did not like the idea of hot 120v A/C flopping around.

The next pic is a close up of the circuit that controls the relays. Note the heat sink on the zener diode. In the end after much circuit tweakage it cooled down but by that time I had already done the heat sink and a little fan to keep the sucker cool. :cool:

Then there is the final assembled and installed supply. There are two toroids on this supply. I stacked them one on top of the other.

Finally there is the circuit with a parts list.

Warning, warning, warning, this electrical stuff will start fires and can kill you. OK, I feel better now. Seriously, be careful. 18,000 uf caps do some crazy stuff. :eek:

Why is this Old School? Well I chose to use relays to cut in the resistor that controls the in rush current. The higher tech methods are to use an active circuit with an SCR or a thermistor. The thermistor seems to be the component of choice for these unregulated supplies. But I didn't want any residual resistance hanging around so I went with the relays. I could not figure out the SCR until much later. Next time maybe.

So the last problem I had was that the bearing block was over bored and the bearing at the top of the screw on the Z-Drive was hitting the oil fitting for the J-Head.

After looking at it some more tonight with the ball screw nut shells loosely in place I determined I could reduce the length of the screw by ~ 0.5 in. and still be OK on the travel.

So I put it back on the mini lathe and turned it down. I'm getting a lot better. I managed to get it right! 2nd time on that one. I've determined that I need to use a "rule of on half". That is I take off half of what I need to once I get within about .010 of the diameter I am looking for. That's a quarter of the change in diameter I am looking for. Given my flexy bendy mini lathe that allows me some room incase it does something stupid when it hits a hard spot in the metal. It also gets me to the point where I am taking off less and less with each cut thus stressing the lathe less and making for a more accurate cut.

I also got started on the new bearing block. Just got the next chunk of 4 x 1.5 bar stock cut on the band saw. I'm going to make the new block just so I feel better about getting it "right". I could loctite the bearings in there and it would work, but I want to get the boring process wired better. Practice makes perfect. I'll start milling the new block tomorrow night, maybe.

Pics below.

In the first one you can see that it now clears the oil fitting. It will be ~0.25 lower than that when I remake the bearing block.

Second pic is the partial assembly with the nut shells on the screw. No balls in there, just the brush seals holding them up.

Third pick is the bar stock getting cut. Real exciting that one! :tired: But if someone has never seen a metal cutting band saw, it might be interesting.

Got it done! Had one more "paper weight event" and a near miss but got it done. The process was about the same.

1. Cut the block and face all the sides to make it square
2. Drill the bolt hole (I bored it last time, drilling is close enough)
3. Notch the block
4. Bore the bearing journal

The boring was the hardest as it has the real tolerances. I ended up with a pretty good press fit. I needs to be pressed in but it's not too hard.

The bearings are 1.850. The hole ended up being between 1.849 and 1.851 depending on where you measure it. I was shooting for 1.849. I've seen this on about eight attempts to bore things to fit bearings. The lathe is more accurate by nature I have determined. On the mill +/- .002 is fantastic.

What I am doing is stopping at about 10 thou and then going a thou (.001) at a pass from there. On the boring head and the lathe that means half a thou. Of course the graduations are .001 so the .005 is a bit of a guess.

The tooling marks are often about .003 deep from what I have observed too. A .002 cut will get most of the previous pass. .003 will get all of them. Again on the lathe or boring head that's .006 net.

I got my hands on some tooling for free. A guy I worl with who used to be a machinist full time before he got into computers gave me a box-o-stuff. One of the tools was a freshly sharpenned 3/4 inch roughing end mill. I have been using 1/2 in finish end mills. This 3/4 inch roughing tool can really remove some stock. I was able to take out about 0.40 at once and I think I could do more. Note, make sure the collet is really tight. It pulled itself into the work about 1/16 inch during the cut.

I'm going to get a 3/4 inch smooth end mill. I think this will help the stiffness of the rig and make for better cuts where I can use a 3/4 in. tool. Anyway, it was a really enlightenning experience.

Along the way I fixed up some splash shields for the coolant. This is working pretty well now. I ran across some pieces of plex that I got for free. It's actually too thick at 1/4 inch. 1/8 inch would be better. It doesn't need to be bullet proof.

I then used my $20.00 heat gun from Kragen to warm the pieces up and bend them into "L" shapes. Now they stand up and can be clamped together in any number of configurations.

I also leveled the machine. It was just sitting on the garage floor. The coolant was running to one end and the back. This caused overflows on the coolant channels on the Kurt vice. With it level the coolant is running off the vice much more evenly now. Big difference. Still getting some on the floor, but a lot less.

The KURT is one of the best investments I have made in the past two years.

To go with is I just got some 0.5 thick parallels. These and the vice have cut down my set up time by probably hours a day. That's a lot when you only have weekends.

It was pretty easy. Just used a 24" crow bar to pry up the front or back and put some aluminum shims under the corners to make it level.

I was looking at a Tree Journeyman mill on e-Bay. This was the first time I noticed some channels cut into the edge of the table on a CNC mill. That would be nice. The new Bridgeports have the same thing I think.


Pictures:
Some pictures of the bearing block

The KURT with the parallels holding up the block before tightening

Milling the notch in the block with a 3/4 in. roughing mill.

Thank you for sharing your effort jdelaney44, nice work.

Anyone one that machines and does not get a little pumped up over your work is one of two things, already done that or dead :D

The true BPT CNC iron such as on the BOSS machines do have the coolant "gutters". The series 1 machines and the converted knee machines (EZTRAK and V2XT) do not have this feature. Unless you have an enclosed machine, you will have coolant on the floor. Even if you have an enclosed machine, it may still leak.
It looks great so far! I wish you well.

George

George & Ken thanks for the positive remarks. I'm glad to hear my work is of interest and that it looks good from there. As a new guy it's hard to tell if you are on track or not. These forums really help a great deal.

Equally glad to hear that coolant on the floor is normal. Well....maybe five gallons of epoxy paint and mop would be the next logical step. The garage would look prettier too!

Best,
-jd

Just a quick hint. A long time ago I was a R & D machinist in a prototype shop with linoleum square tile floor. It turned black rather quickly from oil and chips. I found that FUTURE acrylic floor polish on the floor AND THE MACHINE worked great. The chips slid right off the machine, and the floor lasted a lot longer before it turned black.

George

Been busy this week. Sorry I haven't posted. Work, family, and my HOA. Jeez, too much going on.

The Z-Drive is taking shape. The top bearing block is done and the side plates have been surfaced. I've got some centering issues between the two blocks. Oops. But I can fix them. Just about got the boring thing down pat. No paper weights on this one!

Temporary diversion on some coolant problems. I got too much oil in it and it started to stink real bad. I've introduced an aquarium bubler and a little bleach and things are OK again. Thanks to the folks at DIY-CNC for advice on that one. I found a $149.00 skimmer called the Skimpy. It's on order and should be here in a few days.

http://www.skimpyoilskimmers.com/4436/23932.html

Should take care of the small amount of oil I have to deal with.

I ordered some of those Loc-Line splash shields and modified my coolant sheild rig in general. Trying to reduce the bulk. I bolted a couple of pieces of plex right to the KURT vice. That was a big improvement. Steadied things up. There are 1/2" bolt holes standard on either side of the jaws. Seemed to be a perfect place to bolt up the splash shields. So between that and the Loc-Line shields I think I'll be even better off. This coolant thing can be messy. But I'm gaining confidence cutting at higher speeds and now the coolant is becoming a real requirement.

Also, found a local guy to sharpen up about a dozen end mills I have collected. 1/2 in and 3/4 in. Charged me $50.00 for the whole batch. Seemed good based on his rate sheet. They look OK to me. I'll try them out in a few days.

No time to post pictures now. This weekend will be all family stuff, no machine work.

Well, it looks like I'll be spending around $8K for my Bridgeport Clone conversion also, but via a very different path.

The basic machine cost me $250 (the head was making noise and the brake didn't work, but $100 worth of parts fixed that).

Today I ordered:
1 -- Elrod X, Y, Z ballscrew and axis conversions with replacement yoke (around $4500).

2 -- pico systems drive electronics (say $600).

3 -- $175 worth of connectors

4 -- Capacitor from Mouser (around $40), 1000KVA transformer from Plitron ($112.) Rectifier and bleeder resistor from Digikey.

I'll scounge a case and maybe a computer -- or get a used computer for $100.

I'll be running EMC (which is FREE).

I'll start assembly when the ballscrews get here -- next week, I hope.

I've got to fix the lighting in the shop so I can get some good pictures.

Ken

Left out the servos -- $600 for reliance motors.

(Also, it sounds like jdelaney44 is having a lot more fun, but I need the machine in a hurry.)

KL

Ken, sweet deal on the machine! I wish I had shopped more or bargained harder. But $250.00 is a stroke of divine intervention. I'm jealous! :D

Anyway...some additional pics.

Current stat of affairs with coolant control
The two blocks on the screw
The parts for the Z-Drive so far
The material before I started

On milling the plate. Took two passes on each side minimum. The first pass was to relieve the stress. It was curved to begin with. It was curved differently after that. The next pass(es) began getting it true. The amount that metal can move by simply removing the outter layer has always been amazing to me.

It's easy to understand why coolant is important with dimensional stability too. Getting a piece like this hot would really deform the metal under milling and yield very odd results once it cooled.

Happy Easter!

-jd

Here is a tip from an old machinist who had a S1STD on a vinyl tile floor for 8 years where he worked making prototype molds and machine parts. The floor turned back very quickly due to the cutting oil I used (typically applied with a small acid brush). We have all been there. But we were part of the engineering department and we had to look good for visiting customers. Here is what I found:
USE FUTURE ACRYLIC FLOOR FINISH. After cleaning the floor. Apply the Future. Believe it or not, it worked so well that next the machine was cleaned and Future was applied to it. The chip slid off! The oil stopped staining the floor and machine. True that eventually the Future had to be reapplied. Fly cutters and walking on chips can damaged a finish. But try it!

George

George, thanks for the tip on the Future. One of these days I'm gonna tile the garage floor. That'll help the cause.

So, this weekend is going to be a bust too. Got paper work to do. BUT, last weekend was great. I got the major parts for the Z-Drive nearly done. It is now taking shape. See photo.

The tooling I had sharpenned is working great. Alpha Precision in Huntington Beach. When they are sharp I am getting great results in the 1018 steel. The carbide work he did was good too. As long as I don't screw up they are staying sharp.

I crashed one of the 3/4 in roughers into the work at like 20 ipm & 1200 rpm & .30 deep. Little too much too fast! Things got red, sparks flew, stuff like that. Oh well.

But everything is fitting, is coming together square, and looks OK.

You can see in the picture that the ball nut is not together. That's just for layout purposes. But that's what it's going to look like.

When I get this done I'll post some kind of drawings with the as is dimensions. They are all wierd 'cause I'm designing as I go here. That saves a little time, but not much. You end up having to work to what you did on the first part. So all the odd dimensions just follow you around.

More progress on the quill drive.

This weekend saw me get holes made for some rolled pins providing some alignment at the corners of the frame and holes drilled and tapped for the bolts. 3/8 in bolts and 1/4 in pins were used. This is the first time the whole thing has been bolted up to the Bridgeport without any clamps holding it together.

Pretty stiff as is. I'm going to attach the top of the frame to the machine via the 3/8 in studs that hold the top and bottom half of the J-Head together. Need longer studs. Hopefully next weekend I'll get the brackets made for that.

Pictures below.

Got the "chasis" for the quill drive done tonight. Instead of attaching to the old quill feed lever on the right and the quill feed speed shift housing on the left I went for the 3/8" studs that hold the head together. Not sure I've seen this approach before, yet. Nothing new under the sun usually.

Major accomplishment for me. I got all the parts made, they fit and the screw turns fine. Now onto the motor bracket and the link between the nut and the quill.

This week's experiment with materials was hot rolled steel. Not sure of the alloy. Behaved better with respect to deforming when one side was milled or cut.

Pictures of the mounted drive chasis below.

Never mind........... Questions? Please contact me off list.

Thanks,
-jd

No pics yet. Long day. Too tired. But the motor mount is done and the motor is on the quill drive. The Bridgeport was very reliable today and I am getting to be friends with it. The Trak DRO is behaving too.

Not sure if I made it clear but I decided to mount to the studs coming out of the upper part of the tranny. This makes the assembly a narrower. I also decided to put the motor on the right. This will interfere with the quill handle but this is less to deal with than all the stuff on the left. I'm also trying not to disable the stock quill feed. I'll still have to un-bolt the link to the quill but at least if the CNC craps out I can still get something done in a pinch.

Last week I crashed a screw hanging down from my Kurt vice into the Trak sensor. Broke the mount for the Trak. Got hold of them and they sold me a new mount for $ 45.00 plus tax and shipping. Got it in two days and had it running by Thursday. Yay!

I half busted my 1/4 end mill today but I was able to keep it going long enough to finish the motor bracket. Need to order two more.

I think that's about all the drama for one day!

Next week I need to make the thrust bearing retaining ring and the quill drive will be done. Hopefully by Memorial Day I'll have a CNC mill! Taking the Friday and Tuesday off so I can go full bore on the X & Y drives. I want to at least have the mechanicals done by then.

Later,
-jd

Pics of the quill drive with motor attached.

JESUS! The size of that ballscrew and the motor, you sure that little spud of casting your bolted to is going to hold up???

Nice work! looks very profesional. keep those pictures coming.

Well it's also supported on the studs coming out of the tranny. But, yeah, I even think it's a little bit on the big size.

Actually I'm builing a CNC punch press! :D

-jd

Keep up the posts!

Scott

Started a couple of weeks ago. There's this grindy / squeaky noise up in the vari drive that could be the belt but there is a clear metal on metal sound.

Then today when I was cutting with a 2 inch four flute fly cutter I get this rattly sound like a bearing that's run out of grease and is what I call "spinning out"

So into the vari speed I go. If anyone has tips I'd sure appreciate it. I saw the posts on belts and wear in the head. I'll take some pics and post later.

So the quill drive project is going to have to wait a bit.

Nuts!

Update:

I think it was just a loose motor bolt. I tightenned that up and it sounds OK. The belt is squeaky. It is really noticeable at low rpms. I have a VFD so I can slow the motor down. So maybe I'll order a new belt.

-jd

The Bridgeport 2J head is still making the rattling noises. Replies I have received here and a couple other places indicate that the plastic sleeves and keys in the varispeed are probably the culprit. I think I'm going to work it through next weekend and then open it up. Sounds like I'll get a new belt too. Thanks to all who have relpied for all the help.

Today I got the thrust bearing retainer done. Along with that I made a spacer for between the bearings anb another to make up the extra space between the last bearing and the retainer.

I super glued my material to the face plate of my 7x12 lathe to turn it down to size. For the retainer I super glued it to a chunk of aluminum and put that in the vice. Machined it from there. I heard about the super glue trick a couple of years ago on the 7x10 mini lathe group on Yahoo. First time I tried it was this weekend. Worked great. Just take it easy though. Too much force and heat will pop it off. Once your done just get a putty knife under the edge and tap it with a hammer a few times. Should come right loose.

There's a picture of my centering indicator. If you've not used one of these, they are great. there's a probe that rides on the edge of the hole. There's a small bar that lets you keep the body facing one direction as the core turns with the spindle running at a very low speed. The core has the probe on this little two way fulcrum arrangement. As it goes 'round the body moves up and down and the guage moves. The closer you get to center, the less it moves. Minimize the wiggle and you are at center. I use it almost every day I work. Realy helpful when you skip a step by accident. I got that one at Little Machine Shop.

I also took a picture of the quill drive with the parts loosely assembled. Might help see how it's constructed better.

Quick update. Last night I got the end of the ball screw bored and tapped. Used .25 in end mill. Stood the screw up in two V-Blocks. Bolted the whole rig to the table. Centered it with the centering indicator. Still a little wobbly but OK. The .25 would have been too small for the 5/16 tap really. The typical three lobed hole from the wobble made it reasonable to tap.

Once that was done I bored out some washers to go over the .625 screw end and make contact with the thrust bearings. Put the pulley on, added a couple more washers for the 5/16 allen cap screw, cranked it all down and I have a complete thrust bearing assembly! A little loc tite on final assembly and it's good to go.

Now for the link from the nut ro the stock Bridgeport quill and it's done! Yay! Getting close.................

Pics later.

I know this is getting old, but, here's another progress note.

Today we have the link almost done between the ball nut and the quill. I think I can safely say that paper weight #4 has been avoided.

My best efforts to measure everything with no reference points came out pretty good. But I need to elongate a couple of bolt holes to allow for some slop that has built up through all the parts and at least one suspect measurement. (Quill to ball screw) I can't actually get that measurement so I'm having to build it up from several others. Something is off by about .050.

The link is actually a block of steel that is 4.00 long and 3.40 wide. There is a notch that is about 1 x 1 to accomodate the existing scale and the lugs behind it. The nose of the piece is 0.745 dia. and about .40 deep. This let's it clear the face of the casting housing the quill. The 0.745 just fits in the round recess in the quill. It has flats on either side. So the height is 0.745 and the width is 0.62. So its a round nose with the side trimmed flat.

This is just like the depth stop that was removed. Then on the outboard side there is a "U" " cut out to accomodate the screw. Then there are two 5/16 holes to bolt it to the nut.

So next weekend will be spent doing that and assembling and testing the drive with simple fwd and rvrs on the motor.

As soon as my daughter lets me use the camera again I'll post some pics! Argh! Teenagers.........

Thanks for listening.

It looks great so far. I've got the same kind of project coming up soon, so any threads on the subject of BP retrofit are of much help. All of the pictures have been wonderful! Don't underestimate how helpful they are to all of us.

*All posted by a teenager eager for more pictures :)*

Been following this post with interest. I am also retro fitting a bridgeport and have the X and Y completed and am using the 2 Axis to machine my Z brackets. I am just behind you in progress, presently I am machining the quill/ballscrew coupling out of an 8.5 inch Dia lump of steel (was only piece handy ) Hope to have it completed this weekend.
Hood

Hood, you are faster than me! Yeah that was the right process. I wish I would have done the x / y first so I had the CNC to work with on the Quill. So you're hogin' out of a chunk of round stock? Cool. Should be interesting.

OK kids, here are pics of my Bridgeport Quill Drive Link. Last part for the Quill drive! Almost done with this and ready to do the X / Y.

You can see the big notch on the side to clear the stock scale on the Bridgeport. The hole is 3/8" to accomodate a 5/16 allen bolt. That ove bore is just shy of .75. .625 would do it, but I did not have a .625 end mill handy. Gotta order a couple tonight.

The big "U" wraps around the screw and the two holes in line with that are for the bolts to connect the link to the ball screw nut flange. Again 5/16. So those are the holes I need to elongate and I need to countersink for the allen bolts.

I left all the material there 'cause I figure it'll help make it stiff. There's a limit to how much is really helping I know. But mass is not an issue for this part so why bother removing material that might help?

Have fun!

-jd

Yep its a big chunk of steel I am hogging it from, stupid really but its all experience LOL. Heres a pic of what I have done so far, going to make a bracket going to the downfeed selector lever to help support the top. Just hope my motor is going to be big enough, was assured by the guy I bought the drives off it would be, but he also said his drives were the best :rolleyes: suffice to say I now have Geckos on their way and have already replaced his breakout with a PMDX122
Hood
http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/ZBracket1.jpg
http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/ZBracket.jpg http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/QuillConnector.jpg

That looks really good. The screw is real close to the quill. Key point from what everyone says. Did you have to tap the lugs for those smaller bolts holding the back plate on there or were there holes there already on that mill?

-jd

Actually the ball screw is quite a distance from the quill, see new pic. I would have liked it closer. With me mounting the motor at the top I had to leave enough room for a pulley, also the nut on the ballscrew is 50mm Dia so that ddidnt help either. Yes, had to drill and tap the casting, decided it wouldnt do much harm and seemed the easiest route.
Hood
http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/Z_AxisSide.jpg

Well, it looks like you'll have plenty of travel. I'm losing .75. Not a big deal but some.

-jd

Yay! It's done. This a.m. I elongated the bolt holes on the link. Made a couple of trips to OSH for nuts and bolts, and oh SH*&! I forgots, and got it put together. Assembly went kind of like this.

1.) The sides went on first and were left loose on the transmission studs. Also the bolts to the struts going back to the tranny studs were left loose.

2.) The ball screw to quill link was installed on the quill and tightened down good & tight. Check the quill for free running. No scrapes, good.

3.) Put the bearing blocks on the screw and insert the screw & block assembly into the sides. Bolt up loosely.

4.) Bolt the quill link to the ball screw. Turn the screw by hand to make sure there are no problems along the entire travel.

5.) Turn the ball crew until the quill is fully extended, link all the way down.

6.) Tighten the 5/8" nut under the bottom micrometer depth stop indicator lug.

7.) Turn the ball screw until the quill is fully retracted. The ball screw nut will be at the top.

8.) Tighten everything else up.

9.) Install the pulley, thrust bolt on the end of the ball screw, the motor mount, motor, tighten up the belt.

10.) Apply power and watch it run!

11.) Think - Hey, I did that!

12.) Drag your significant other into the garage to watch as she / he looks at you as if you are nuts.

Thanks,
-jd

Drag your significant other into the garage to watch as she / he looks at you as if you are nuts.

Thanks,
-jd


This is a daily occurance the my household!

Nice job!

Looking good JD, great to hear its working fine as well, just hope mine does when I get it finished. Not had a chance to get anything done to mine :( the head started making lots of horible noises mid week and think the bearings have gone. have a spare bridgie and have been swapping the head over this weekend, man they are heavy, even with the motor and belt housing removed.
Hopefully next week will see it completed, geckos are scheduled for arrival tomorrow so the scrap drives I have in now will be removed.
Look forward to the rest of your conversion.
Hood

The motors I have are 100V Reliance Micro 100 series. The temp power supply I made is 33V. My final supply will be 56V. So, I have been concerned about the torque.

I decided to use a 3 to 1 reduction based on a couple of "rule of thumb" statements I have seen out there.

So......I decided to lock the quill down last night to see if I could measure the flex in my drive. No go. The motor pushed the quill right out of the lock. Then I put my plastic shot filled mallet under it. It squished it down a good 1/8". So....there is plenty of torque using a 100V motor at 33V with a 3 to 1 reduction and a 5 TPI ball screw. Once I get to 56V there should be no problems.

Thanks,
-jd

My understanding is that the speed is proportional to the voltage. The torque is proportional to the current.

So, running at a lower voltage will reduce the maximum speed, but should NOT affect the maximum torque (within some limits). Obviously, if the voltage is too low, it cannot drive enough current into the motor, but that is not usually the case.

Ken

So here are some drawings of how I've envsisioned the X-Drive on the Bridgeport. These are exploded.

I did pencil and paper for the Quill. But after making several errors I think I could have avoided, I decided to invest the time with the CAD. I think in the long run it'll be faster.

You'll see a four bolt pattern on the inner and outer plates. Thisis for a couple of bearing blocks. There will be a 5/8 in. shaft that goes through those to a coupling that will join that to the ball screw. When I replaced the ball screw I got the one to go with the existing Bridgeport power feed. I did not want to disable the ability to put the machine back into the condition it was when I got it. Again, incase the CNC craps out I want to be able to use the machine to make repairs if needed.

The drawings don't look great in the browser. You might want to download and open with something else. My Turbo CAD's save as to JPG is less than great. I'll keep working on it.

Thanks,
-jd

JD hows your X and Y going????
I have got my Z completed and working and have actually made some money with it :) Will be a while before I get my costs covered but what a machine, still got limits to fit and cables to tidy but hope to be moving workshop soon so might wait until then to do the snagging. Also I am a very untidy person as you will see from the pics so I feel at home wth things being half finished :rolleyes:
You can see my x y and z pics HERE (http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/BridgportConversion.htm)

Hood

Hood, I started the X today. Should have it done tomorrow. Going well. I'm trying to get the Y done by the fourth. I've got some personal stuff hitting the fan right now so that's slowed me down quite a bit. But, so far so good.

Thanks for the links. Looks good. Glad to hear it's working good too!

-jd

Look forward to pics of your finished X and Y. Today I hope to get my limits fitted so I will be happy to leave it alone and get on with other work while the Bridgie does its stuff.
Hood

Here are the pics of the X-Drive. Just about ready to mount. Note the shaft. I have a screw designed for the Bridgeport power feed so I am making the x-Drive to fit that.

-jd

Some more on the X-Drive construction.

(as always please pardon the spelling and typos)

The CAD exercise helped a great deal. I have previously just been slugging it our with pencil and paper. I use TurboCAD 11 (TC). Just got the upgrade in the mail yesterday. I've decided that CAD programs are a matter of personal choice. The 3D operations in TC make sense to me. They also have what, to me, is a pretty intuitive control for sizing and dimensioning objects. I haven't tried them yet, but the auto dimension features in 11 are supposed to be better. The dimension features in 10 allowed me to quickly set up the dimensions you see in the clips above. I need to reload those too. Just notices I managed to load the same drawings like four times. Nuts.

These drives are aluminum since I am not as concerned about the rigidity as I was on the z-drive. Actually I over killed on the z-drive. More on my observations there later.

So this time around I decided NOT to surface the stock like I have been doing. My rationale was a.) I see a lot of other people getting away without doing that, b.) the belt stretch should probably soak up and deviations created by the inconsistent plate thickness, c.) I can shim the drive and the motor to get perfect alignment if it does become an issue, and d.) I am using flanged pulleys so the belt coming off should not be a problem, and and e.) the material deflects when you surface it anyway so the true gain is really very questionable.

Still everything coming off the bands saw had to be squared up on the edges. I do this by picking the best looking side and putting it down in the vise. Then I mill the one edge sticking up with either a 0.5 or a 0.75 end mill. Then I flip it over and do the same. This time though I'm checking dimensions as I go. I currently over size the stock on the saw by about 0.25.

Once I have two sides parallel, I clamp the piece flat in the vice using a couple of steel parallels to hold it at the top of the vise. I got a set of these for $99.00. 0.5 thick by 6 inches long.

Once clamped I run the side of the end mill along it in the Y direction. One deep cut to get it close and and then one or two finishing passes to get it pretty. I have taken to running the finish cuts at about 0.002, dry no coolant, with the rpm at about 1500. Now turn it over and do the same this time working to the final dimension.

This go round included a run to Harbor Freight to get a set of 12 inch calipers.

Six finished parts one paperweight. I'm getting better! - This time the DRO was being squirrelly. I had to recalibrate it. Unfortunately I did not discover this until after I made the motor side plate and checked the dimensions. Everything grew by about .002 / inch. In the 12.75 inches of the plate everything looked perfectly proportional and accurately spaced. But it was WAY off by the time you got to the end of the plate. :eek:

I debated for a long time about not fixing the DRO for the balance of this build. It would be wrong, but it would all be the same wrong, right? :o

Well, then I figured if I ever want to make spare parts or retrofit something in there I'll be fighting these odd dimensions for the rest of my life. Forget that. So I remade the motor side plate.

The slots for the motor mounts screws are 1/4 inch. They are 2 inches center to center of the end radiuses. I did this to give me a lot of latitude in belt sizes. You never know when things break if you can get what you want, when you want it. This Just In Time world we live in doesn't always work out so good!

To cut those I plunged, slowly, the 4 flute HSS end mill all the way through the 0.5 at one end and ran it to the other end with the power feed at about .75 ipm. Real slow. I actually adjusted it by ear. When I heard a smooth cut I kept that speed. Oh, The end mill was in the collet right up to the top of the flutes. I got way too much chatter with it sticking out any more. The slots came out OK. They are smooth and the ends don't have too much of a deviation from what I will call recoil. Coolant was used, yes.

The slot for the motor shaft was made by running the same .25 end mill around the perimeter. I hand calc’ed the end points and used the DRO to tell where I was.

Note that I zeroed the DRO using an LED edge finder. It was zeroed at the upper left corner of the part, same as my drawing dimensions so I didn't get confused half way into the operation.

Note on using the edge finder. When I got it, the directions said not to have the machine turning when you used it. That made NO sense to me. I think they must mean high speeds.

I know I have about .0025 of runout in the spindle. So what I do is turn the spindle at like 10 rpms (using the VFD to slow it down). Then I crank the part over until I just get a little blink out of the LED as it grazes the edge. The tip of the finder is .20. So then I know I am .101 - .1015 or so away from the edge. This offset is then set in the DRO for X, repeat the process for Y. You now have a pretty good home setting in the DRO. I say pretty good ‘cause nothin’s perfect ever.

Hmmm……To make this better, I need to really put edge finder in the collet and mark the position somehow so I can get it in the same spot every time. Re-check the total runout periodically. Then use the same collet, the same edge finder, all lined up the same way every time. And make sure the R8 tapers are spotless of course. If I get a dog hair in there I’m off by .002.

So lets see. Do all that, then put in a three jaw drill chuck with a stock #10 drill bit in it and pray for +/- .005 as that wobbles around. Hmmmmm. Such is life.

See posting this stuff helps work things out!

The big deal is turning the spindle slowly and looking for the LED flash. That gets me a lot closer to compensating for the runout.

The back side was easier as it just has holes, no slots.

Then came the drilling of all those screw holes. Decided to use 10-32 x .75 screws. I thought that was going to take forever. It took about 45 minutes per big side and 15 minutes for the small sides. A #10 drill was used for the front and back plates where the screws would countersink flush.

I settled on drilling a line of holes, and then going back and counter sinking that line. At first I thought I might get lousy countersinks. But the machine and DRO seem to be holding +/- .002 or better so that's no problem for a drilling operation at all. So I drilled on side of holes, change to the counter sink bit, and went back to where I started that line, then went 90 degrees along the next side etc... I did get away with not locking the table as these were small holes with little chance of enough force being developed to move the table while drilling. This was done with an regular three jaw 0.5 in drill chuck on an R8 arbor. Cheap Chinese one. I need to get a Jacobs, they work so much better I can't even describe it. Actually I have the chuck for the late, just need the R8 arbor for it.

So now for the short sides of the box. Ran out of 0.5 plate, so I switched to some 0.375. The holes are slightly offset to make the outside smooth given the original design called for 0.5 through out. No big deal. Drill the holes as before just with a #21 drill this time for the 10-32 tap.

Tapping was accomplished by chucking the tap into my 1/2 VSR Milwaukee drill. Nice drill, lots of torque. Very carefully used the drill motor to drive the tap in. Reversing when the resistance got too tight. About 1/2 a turn to relieve the chips. Took some time, but not as long as it would have hand tapping them all. This also required that the tap be allowed to find it's way square in the first couple of threads. Which worked pretty well as long as I eye balled the drill to be square to the part. Some day I'll be able to afford a Tap Matic. Still, no busted taps this time. Yay! :D

Now everything is square, slotted, drilled, countersunk, and tapped. Assembly time! Much to my shock and awe, it all fits and ALL the screws go in easily. (The sun shines through the clouds as the organ plays and the choir sings for a miracle has truly just occurred! :banana: ) (Ok I just HAD to use the banana icon, sorry)

The only problem I found was that my pulley is hitting the bearing block on the inside, so just put the block on the outside and problem solved. I may still see if I can work that out somehow.

Onto the Y-Drive CAD drawings............

Congratulations.

Thanks for documenting what your doing. It has been very helpful.

You are very welcome, thanks for the kind words.

Lookin good JD.
What software and drives etc are you using? Sorry if youve already said but I am too tired to read through the whole thread again, either that or just too lazy :-)
Ive been working on mine today, got all the limits working and also have a speed sensor tested, just got to make brackets for it and cut a slot out a pulley.
Hood

Hood, well, I'm probably going to go with the flow and use Mach 2. I've got the Sound Logic break out board and I've got the Gecko G340 servo drives. Turbo CNC still looks interesting as do a couple of other DOS packages. But Mach 2 has grown to become almost a defacto standard in the DIY community. Almost.

Eventually I would like to revisit EMC which is Linux based and has the capacity to do true feed back to the software.

With the Geckos and Mach2 I get basically an error trip when and if the motor gets 128 steps behind. Then the Gecko faults. With the error signal I can trip a general e-stop in Mach 2. With either software you have to stop and re home and start the program over. I don't think EMC has the ability to dynamically adjust feed rates based on the ability of the servo to keep up. But that would be cool. Art Fenerty has talked about doing this with Mach, but I don't think he has yet.

Thanks to one and all for the positive remarks and replies.

Best,
-jd

These are hopefully a little better than the last ones. I got the TurboCAD 11 upgrade and the JPG generator is supposed to be better. They still look bad on the browser. But they looked OK in a photo editor.

Hows it going JD got the Y started yet? Would love to see some pics of your completed setup.
I am amazed how easy and quick CNC is, obviously I have a lot to learn and I think I will always be learning, but I made a lid for a seacock for a boat the last day and had to cut a 1inch hex on the top for a spanner. Previously I would have hauled out the old Hartford Super Spacer and machined it that way but I had the code written, brass clamped to the table and the machining done before I would have had the Hartford set up :) I love CNC :banana: (i had to use the banana as well :rolleyes: )

Hood

BTW have been building the control box for my next project, have been so impressed with the Bridgeport that my Student Lathe is next for the retro, will just have to wait until I can afford the steppers though.

Hood,Cool beans! Well if you can sell a few parts you can get some more steppers!

Uploading a couple of DXFs that might be handy. One is for a ten tooth L series timing pulley. One is for a 30 tooth. These are not detailed, just the outlines. I'm using them this way so my puny Celeron doesn't get too slow.


-jd

JD, dont know if youve seen this but think it might be of interest
http://groups.yahoo.com/group/mach1mach2cnc/message/35796

Hood

I did see that. Yes! Mach is going to be closed loop and function as a DRO too! Well with the addition of that board they are building. Sweet.

I'm really jazzed about that. There was a thread on that whole thing at CAD_CAM_EDM_DRO. A couple of people were tweaked that Mach wasn't closed loop. This has actually been debated a lot and the conclusion, I thought, was that it was no big deal 'cause it worked pretty good. But this is a big change.

I was beginning to think about trying EMC again after reading all that. But now it looks like I won't have to.

Thanks for the heads up.

Here are the JPGs of the Y-Axis Drawings. Construction starts tomorrow. Maybe I'll get the box done tomorrow. I hope. I hid the side on that last isometric / exploded view to show the pulleys. I've used simplified block drawings of the pulleys to keep the load down on my PC. Same thing with the screw holes this time.

Once I get this built and both the X and Y fitted I'll post the .DXFs. Just don't want to set anyone off on a goose chase until I know all this fits and works well.

Well, I did not make much progress today. The light switch in the garage broke so that turned into three little projects and a stop at my parents house to say HI! Hours latet I got started. THEN I crashed the vise into the column and threw that out of square. So that meant a vise remount. While I was at that, decided to cut some flats into the 5/8s bolts so they engaged the T-Solts. Etc........

But I did get the material rough cut for the front, back, and sides. I did a couple of unusual setups. So I figured I'd post pictures of thos activities.

-jd

Shame you never got started yesterday :( cant wait to see your finished Y.
I am hoping to get some MPGs fitted towards the end of the week so that will make edge finding a lot easier than jogging by keyboard. My plans are to build a seperate console and have a keyboard with a touch panel to do away with the mouse. Heres the keyboard I was thinking of getting http://www.kustompcs.co.uk/acatalog/info_3003.html

Keep us updated on your progress.
Hood

Interesting keyboard. I am not a touch pad fan. I can never get the hang of them. I prefer the track balls like that Kensington track ball. Logitech had a wicked good track ball a while back too. They may still.

More on the pics above. I say unusual because the pieces are almost 24 inches long and .325 / .40 thick. So at the ends they get pretty wiggly. Also they were too long and too deep for my band saw. So I had to cut them with a .25 end mill.

Laying them flat on the table was no big deal.

But up on edge to start to true them up was due to all the material hanging out in space, I happen to have a couple of these angle irons that have been milled square, well pretty square. This shop in Costa Mesa sells them. They are good for structural welding & such. Not really square enough for layout. But, good enough to hold the ends of the material. So once I had the material in the vise I clamped the angle irons to the table and then the material to them. Did the trick. No chatter. Nice and quite. Lots of chips.

More later.

Well, somehow I got the centers wrong on the X & Y drives. Not a lot. Can be fixed by slightly elongating the holes. Also the X drive needs a spacer so the bolt holding the bearing block on will not hit the table. So I'll have to make that too.

So if you are using my drawings as a guide, measure your machine first.

Got the back plate of the Y drive done today, except for elongating the holes. All the plates for the Y drive are sized. So now I just have to drill & tap all those holes.

-jd

The last major mechanical part is done. That was the coupler between the X-Drive shaft and the the X ball screw. I got the inside diameters right on the first try! Yay! The holes have been corrected on the X and Y drive.

What was wrong? Measure it three times, draw it, check it, then cut. I think I screwed up step one. There were different errors on each pair of holes. I amazed even me on this one.

The first time I measured I did it with a steel rule. The assumption was the Bridgeport would use "standard" dimensions. Wrong. Close, but no cigar. I also assumed the Y drive shaft would be centered in the thrust plate. It's not. So I measured something that say looked really close to 1.5" and assumed it was 1.5. In hind sight this sounds really dumb, I know. :withstupi Last time I do that.

2nd go round I put bolts in all the holes and measured off the bolts. They had to be snugged up good to get them as close to center as possible. I tried to allow for dimensional problems with the bolts. They were pretty much +/- .002. But .375 bolts turned out to be .370 and stuff like that. .005 is literally a hair but it adds up right?

Anyway, tomorrow is assembly day. Then on to electronic hook ups.

-jd

Cant wait to see it, you will love running it :)
I made mine so I can crank manually as I thought most times on small jobs it would be easier. I was wrong, it is quicker to do evenn the smallest job with CNC and think I will remove the hand cranks soon.
Hope u post some pics.
Hood

These are all as I am assembling it. I did not take pictures of the stand offs. They are just pieces of brass pipe that have been cut to size on the mill and dressed up on the lather.

First one is the front of the Y-Drive.

2nd is the top and the top plate. Note the clearance that I had to cut so the pulley didn't rub on the top. I made the top very close to the pulley so I could get that big pulley in there and not have the box stick up too much. It actually sticks up more than I wanted but it does not interfere with anything.

I would have to pull the whole thing and the screw off to remove the saddle anyway.

3rd is a side view. 4th is a shot looking straight down.

5th is the "Emergency Handle". I needed to fix a couple holes I forgot yesterday but the drive was half assembled. No crank, no CNC, but work to do. Hmmmm..........

So......I saw a 1/4 20 hole in the pulley and thought, "Hey I can stick a bolt in there and use that for a crank". Well after scrounging parts bins I came up with a piece of 1/2 inch PVC pipe, some 1/4 in. flat washers and a 1/4 20 nut. A little work on the 7x12 lathe to cut some seats in the end of the pipe for the washers and some more cutting, trimming, and sanding, and I have a crank handle. So if the computer completely craps out I can pop the covers off the drives and keep some work going if need be. Need to make two more for the X and Z.

OK, on to the X-Drive..............

First is the drive right after the basic shell has been bolted to the end of the table. All those washers are to cover up my errors. Looks OK. But totally bush league on that goof! :confused:

Note the bearing is bolted up in position. At this point the table has been cranked far left. This leaves almost no wiggle in the ball screw. It is stiff enough at this point to force the bearing to the proper center. Tighten it up. Instant alignment!

2nd is another view of the basic shell. Note I have left the bottom off. This is so I can tighten everything up and install the belt. The bottom cover will go on last. The top and sides had to go on first since the screws face the table and are hidden by it.

3rd is with the pulley on the shaft. Not tightenned yet. That will come after the motor is installed.

4th is with the outer plate ready to get screwed down.

5th is with the outer bearing bolted up for position.

6th is a shot from under the drive.

More tommorrow as this progresses. Today was just interuption city. Between parts runs and playing Dad's Taxi Service I lost several hours. Man!

-jd

Hood, I can't wait either. I've read that everyone skips the handles after a while. So you are confirming what I've heard. Thanks for the replies as always. Glad to hear your machine is humming along.

-----------------------------------------------

Today was about getting motors mounted and the drives test run under straight DC current. They ran great. It was so nice to see the table moving back and forth as a result of my work. These are the first real machines I've ever made from scratch. So this is a big deal for me. :cheers:

Then I started making the new encoder covers. I'm making these out of PVC electrical boxes. They were half price of the aluminum, look better, I think, and will be easier to tweak. After they get mounted the motor seams will be sealed up with some silicone, including the brushes. The last thing I need is a fried commutator due to coolant leakage. The Y-Drive is going to be at the most at risk. I might make a little "roof" for it or something as well. Well see how it goes. Actually a gutter to catch coolant running down the drive housing would be the right ticket.

The problems of the day were the shaft lock bushings. These came a tiny bit too big and would not tighten up. So, I wedged some aluminum duct tape in between the bushing and the pulley before screwing on the outer shell of the bushing to the inner shell and it worked!

Design change - Need to open up the slots where the motor shaft goes through so it can be inserted with the pulley attached. Cinching up the shaft lock was a real pain with the motor half mounted to the plate.

Also, the shafts on these motors could be longer. I would like a good 2.00 inches. Alternately the plate could be thinner or pocketed out for the motor. I'm using .375 plate. A .30 or something in that range would be fine. 0.25 seems to thin still, but could probably work fine given the box design. Sides would have to be .375 to handle the screws <IMHO>.

I'm sure someone with an actual engineering degree could calc it.

Little sub projects for the day -

LSPFTD #1 -
Had to modify a couple of 5/8 open end wrenches. Cheap made in India models. I needed them to real thin so I could tighten up the shaft lock bushings. This is when it is nice to have a mill. Ground off the chrome, put them in the vice, chucked up a .75 rougher and went at it. Killed the rougher but got them whacked down to where I could clean them up with a file.

LSPFTD #2 -
The bolts for the outter bearing on the X-Drive kept rubbing the pulley. So took them over to the 7x12 lathe spun it up to full speed and ground the caps down about ~0.10 using my 4 inch Makita hand held grinder. I could have used a carbide tool, but they are grade 8 and I've had a lot of troublewith grade 8 bolts in the past on that little lathe. The grinder worked well. I need to see if I can use the side handle mount hole to get it on the tool post. That would be cleaner.

Only one store run for bolts!

There are some pics of the drives with the belts hooked up and the PVC encoder housing getting started.

Best,
-jd

Tonight I drilled the holes for the liquid tight flex connections to the electrical box. Cut the servo motor wire to length. 12ga 3 conductor, stranded wire from Home Depot. Type SJOOW. Black rubber extension cord wire to me really.

Then the shielding was put on it. I got the shielding from Mouser. So at first I thought this was going to be a real pain in the back side. But it turned out to be really easy. You just push a bulge into the braided shielding and slide that onto the cable. Do that a few times to get started. Then as enough gets on the cable you just "slide" the bulge down the shield already on the cable and smooth it out. Wear gloves or your hands get stained with the aluminum. It scrubs off but gloves would be a good idea.

Yesterday I decided to bail on the plastic j-boxes and go to aluminum. This was after I looked at the size of the conduit. 3/4 inch weather proof flex is almost 1.25 OD. It's big. So I think the aluminum boxes might be better. They are pre threaded for the fitting too. Nice.

Pix tonight are the holes in the cabinet, the wiring supplies, cutting the shield to length, slipping the shield onto the cable, sliding the bulge down the cable, the finished cables and the aluminum j-boxes fit to the servo motors.

Best,
-jd

JD
Looking great, wish u would hurry up though ;) I cant wait to hear how you get on with your first cuts. That braid looks great stuff, I looked for stuff like that in the UK but couldnt find it but I am sure it must be available.
Have you decided on software yet? I am loving Mach3, especially all the support and following it has and all the wizards make life really easy.
Hood

Hood:

I'm going to start with Mach. I think, maybe, I'm going to add on that closed loop board to give me some software stop for too many lost steps. The Geckos fault at 128 steps of following error but that's actually about .004 worth of following error on my setup. For what I will ever do I am sure that's fine.

Still I'd like to see if I can get Mach to stop sooner. Maybe at .002. Not sure if that's possible. We'll see. I need to do more research on that.

-jd

Here is one revised drawing. This is the inner plate of the X-Drive. This is the one that mounts to the end of the table. Thought this would be the most interesting as it has the bolt holes for the table on it. I would drill the holes bigger than .375. Drilling is not that accurate for starters. The bolts are always a little off too it seems. At least the garden variety bolts I use are.

But these are the dimensions I used and they are working now. I would print this out full scale and match it to your machine to check.

There is a .jpg and and .igs. The .igs was the only one I could get my Turbo CAD to save and reopent reliably. I don't think their .DXF is 3D. Maybe .DXF isn't 3D, I don't even know for sure. Oh, the .igs is in that .zip.

Let me know if you can or can't open that .igs too if you wouldn't mind.

I'll keep dribbling drawings out as I can. I fix these things up in the wee hours on nights I can't sleep ususally, which is fairly often. :tired:

Back to the shop to get that wiring done............ Gotta clean carpets today too. Yuk. :(

OH, one last thing. I am ditching the shaft lock bushings. I ordered some new 10 tooth pulleys with .375 bores instead of the .50 I had. They got here yesterday. So I will mill a small flat on each motor shaft for the set screw in the new pulley. I've read that this works pretty well.

Best,
-jd

I will mill a small flat on each motor shaft for the set screw in the new pulley. I've read that this works pretty well.

Best,
-jd

It would be much better to just drill a spot through the pulley setscrew hole into the shaft, than to remove more material than absolutley required. Non-keyed shafts, High torque, flats and a setscrew can rock, wollow and roll in constant F/R directions.

DC

Excellent suggestion. I'll try that first.

-jd

Well, the carpet cleaning killed the whole weekend. Then it killed me for three days. Man that's a lot of work!

So....all I've really been able to do is get the conduits run and attached to the J-Boxes on the motors. So that's all bolted up.

What I did here was to make up the conduits first, with the wire in them, and then mount that on the machine. The short run just went in. The long one (12 feet) required help with a fish tape and some soap. Both the motor wire and the encoder wire are in there. Both are shielded. For the encoder wire I'm using Alpha Wire P/N 2424C which is an 18ga foil shielded communication wire. It came from www.mouser.com.

Oh,forgot, I covered the shielding with heat shrink tubing. I had 1/2 inch heat shrink. It was a tight fit so it had to go on in pieces with overlaps. Once it was on the cable loose I hit it with the $19.00 heat gun from Kragen and it's nice & tight.

The conduit is 3/4 in. liquid tight flex with the metal inner jacket.

So each cable is shielded and they are in a metal conduit. Should be OK based on the reading I have done. If my Geckos freak out, this will be the first thing I check. The shields will be grounded at the control box only to prevent a loop. This is what has been recomended by many people.

That's it for now.

It is so bizarre shifting into wire mode after so many months of cutting metal.

Today the mounting plate for the Geckos and the Sound Logic break out board was completed and mounted in the control box and wired up to the motor and encoder wires.

The DC power lead was made up as well.

The Geckos are mounted to the plate with 6-32 x 3/8 machine screws. The plate is 0.25.

The SL board is mounted on 8-32 x 1" screws. Nuts were used to lock the screw to the plate and hold the SL board against the head of the screws thus creating a stand off.

All screw holes in the plate are tapped to accept their respective screws. Used the Milwaukee drill motor again. Got too agressive once and busted a 6-32 tap.

The plate is mounted to the back panel of the box with 5 12-24 x 3/8 screws. The back plate is tapped. Hand tapped on this one. These are through and aluminum angle that is through bolted to the plate with three 12-24 screws & nuts.

Then there are the Diet Coke can bottom heat sinks. I actually think the plate has enough surface area to deal with the heat from the Geckos. But a little more surface area couldn't hurt. I don't really have room for big Pentium heat sinks to tell you the truth.

Next is the motor end of the wires and then its time to fire up the PC.

Pics below.

So....I write you all from the PC that is running on the machine. No pics tonight. Tomorrow a.m. will be the final hook ups to the PC and the servo motors. Then a little testing and clean up. The Garage is a disaster area.

OBTW - My best wishes to the folks in the south. We sent $100.00 to the Red Cross and will be sending another $100.00 at work on the next check. Work is matching too. So that'll be $400 on account of my little tiny chip of the world. Not bragging, just challenging anyone who can give to give. Please give if you can. Anything will help. If you can't you can't and that's totally OK too.

I dropped about another $700.00 this week on parts, Windows XP, a new flat panel monitor, keyboard, track ball, and misc. fastners.

Interesting commentary there eh? Well we do what we can even if imperfect.

Still gotta pony up for Mach 3 tomorrow. I've settled on Mach. If for no other reason than all my other machines are on Windows XP Pro and I'd rather not hassle even a DOS box if I can avoid it.

We are doing Red Hat at work for our Oracle ERP project. Gawd! What a frigin' job. We've had a DBA on hourly for three days just getting a restore from Oracle's data center in Austin to our test machine done. Then there are the RH & Oracle patches. It's just messy still. They are trying to catch up to Microsoft in this area but they have a ways to go.

I think us Windows people are just lazy. Which equals efficient. I'd rather let Redmond do the work.

But....if all goes well this weekend I will be very close to done.

Best,
-jd

:( I hate it when this happens.

Well .... I looked and checked and checked and looked some more and missed it.

I got the polarity reversed out of the supply to the Geckos. Not sure what happenned as a result. Something went *POP* in the control cabinet. Could have been 50 things. Could have just been the fuse. It's got a ceramic body. I have heard them make noises like that.

Now I have to bench test the geckos again I guess.

I am getting about 125 ohms across the power terminal of one of the Geckos now. I've posted on the Gecko forum at Yahoo and DIY-CNC to see if anyone knows what I should be getting or has any other clues. I am praying that these things have a diode across the supply to protect them from such a thing. If so, that's what blew the fuse. (15A Fuse). If not then I've turned something in there into a 125 ohm resistor.

This is what I'm worried about. I've done this before building things with power transistors. You blow it and it either goes wide open or something fuses in there making it into either a perfect conductor or a bit of a resistor. Not pretty.

Gecko is local to me so I'll probably just drive over there on Tuesday if these things are toast.

Well I need to get some more fuses today. Disconnect the Geckos and test the power supply to see that it's still OK. Then I guess I'll feed some juice to the motors and make sure we don't have any dead shorts there either.

If the drives are toasted I'm going to go with the Rutex for the higher voltage. So that will mean transformer replacement on the power supply as well. These motors are 100V. My capacitors are something like 90V so I'd like to get as close to that as possible. The Geckos will run at 75 volts. Rated at 80 but I was told not to go one volt over 80, ever. So 75 seems safe.

Any suggestions out there?

-jd

My reading was off last night. I'm getting 25 ohms on a meter powered by a 3V battery and an open circuit on my digital meter with a 9V battery. Still waiting to hear if the voltage of the meter makes a difference.

Today's readings are better 'cause I'm not poking around with a probe in hard to get at places. I pulled the drives out and bench tested them. Checked it all at least twice.

Powered the drives with about 33V unregulated DC. No other wires connected. Results:

~1.2 amps current draw dc
One drive will not light the fault light and it should
All three have ~5v dc at the encoder supply pins
They all get hot fast just sitting there

So I believe all three are busted and need to go home for repair. We'll see what Gecko says. Yay.

I'm so mad at myself I could spit. :mad: :mad:

Oh well.....

-jd

Well, I have exchanged several messages on this one today. My bet is that I am out three G340s. So....now what? If I have to buy new gear, I may go with the Rutex to get at the higher voltage for my 120V motors.

Hmmmm?

-jd

So the Geckos are on the way home. I ordered a new set of G320s. If the 340s can be fixed I'll have spares or the beginning of the next project.

While researching that little explosion I found some additional advice on the in rush limit circuit on the power supply. That's the problem with this sometimes. You don't know what you don't know.

Seems it is better to have the resistor and relay on the A/C side. Makes sense. The transformer is there to soak up some of the surge when the relay cuts out the resistor bank. No problem. I built the supply in a fairly modular fashion. So with no soldering I should be able to reconfigure it properly. So tonight I began teardown.

I will first rework the schematic so I know what the heck I am trying to do. Then I can rewire it to the new design.

BTW - Green Loctite works! I could not get the nuts off of two of the 1/4-20 studs I mounted the supply on. I ended up shearing two of the studs off with the wrench. No harm, just install new studs.

Pics of the supply below.

1 - The supply with the circuit board removed
2 - Front of the circuit board
3 - Back of the circuit board
4 - Terminals where the transformer windings are ganged together
5 - The 3 x 18000uf 100V cap bundle
6 - The relays, one of which will be eliminated

just out of curiosity why did you stay with the geckos and not go to rutex like you where threatining??

Excellent question. Reasoning went something like this.

1.) The Geckos worked fine in bench testing.
2.) Contacted Rutex, they have no polarity reversal protection either.
3.) The cabinet is now organized for three flat devices not three devices standing up on end.
4.) The G320 / 340 is older and well understood, Rutex is launching a new series of boards now. Not sure about getting into that just this moment.
5.) I would not have to re-do the power supply voltage with Rutex, but should and that means new transformers.
6.) Gecko is very local to me and has thus far been easy to deal with.
7.) I do know how to set them up now, if you excuse my screw up here. No sense in inviting another variable now.
8.) At some level this is a gamble. Not sure now is the time to switch tables.

Do you have any knowledge of the Rutex product I should know about? I can still cancel my order or return the G320s if I am doing something dumb here.

Rutex does have a 50% off replacement policy for damaged gear that can't be fixed however. I did not get all the details on that. Which is nice. But it does tell me that they get busted stuff back all the time too. Makes me feel a little better I s'pose.......

Thanks,
-jd

I am personaly going to use rutex on my servo machine and NO I don't have any knowledge of one being better than the other. Was just wondering if something made you change your mind on the rutex stuff.

You pretty much answered my question about the "why" of it.

They both make quality product and if either one had a facility near me I would probably stick with that supplier, just for the "drive of and B!tch at them in person" factor if they ever screwed me! And not to mention most companies give better service in person than over the phone.

As far as the return policy of Rutex I wouldn't read too much into that, because if everyone was blowing their stuff up, they couldn't afford to give 50% off of returns (fixable or not).

Cool, thanks for the reply. Got the 320s today. Off to the races again. Keep us posted on your progress if you would.

-jd

Having some back & neck problems. Sorry I haven't posted. Maybe next weekend I'll get back to the machine.

-jd

Sorry to hear of your Gecko probs JD, hope your back is sorted soon and you can get on with this project.
I am about to embark on a swap over, I just got a series 1 Boss in good condition and will be swapping everything over from my mill soon. Not been able to test the head yet but ways and screws look good.

Hood

Cool deal. Sounds fun. I'm going to try working on the power supply tommorrow some more. Just about got it going. Hard to make progress 30 minutes at a sitting......but the back feels pretty good today so maybe tomorrow.

Hows it going JD? hope the back is better and you get the retro up and running soon.

Hood

So is my back! Thank god. The pain is workable so back to work on this beast.

Thanks to the good folks at DIY-CNC over at Yahoo I got the power supply rewired today. Two main issues. One, I found a posting from Mariss at Gecko that the in rush limiting stuff should be on the high voltage side of the transformer to buffer the hit when the in rush resistor is abruptly cut out.

Second, I have wanted to wire it so it fed off of the two hot legs of the 240VAC clothes dryer circuit I am using to power this thing. I was not able to get it right last time. Something was wrong and I had this bizarre cyclic hum buzz and pop thing going on. Sounded very Frankenstein Lab-ish. Great for the movies, not so great for my garage.

Long story........

I am using two torodial transformers. I orginally bought them with two 40V secondaries each. They can be wired in series to 80V. I thought this would be OK with the Geckos. Not. The Geckos should probably not ever be run above 70V allowing for line voltage fluxuations that could push it close to 80V. If you hit one volt over the rated 80V, they fall down, go boom.

My 80V transformers were first off..... 80V....., second I learned about the 1.4 factor for turning the AC into DC. The 80VAC we see on the meter is Root Mean Squared or sorta the average between the high and the low of the AC swing. When you flatten it out into DC the RMS is taken away and that increased the voltage by 1.4 times. So now 80V becomes 112 volts. Nuts.

So.......I had to use the 40V secondaries in parallel. That's 40V at 110VAC. My power is 120VAC flavored. So I get about 44 volts out of it. 44 x 1.4 =~ 62 volts. So that's about 18 volts below the max of the Geckos. Safe plus some.

OK fine, wire it all in parallel. Then put each transformer on a different leg so the phases are balanced.

So back to where I was with the hum buz pop thing. The wires from the secondaries were buried under the circuit board and the whole thing was in the machine already. So, I had given up and just wired both the primaries to one hot leg and it worked no big deal.

Since now I had to tear down the supply to fix the in rush placement I decided to try to wire the transformers correctly. Got it this time!

Steve on the DIY-CNC board gave me the tip. Here's how I did it.

This assumes two identical transformers with two secondaries each. Each secondary has the same rated voltage out.

First wire the two primaries in series. I did this by going white wire to white wire. I did this because next time there will be no way to wire it wrong. There are two ways to do black to white, one way to do white to white.

Now the black wires can go to a hot leg each.

So now get all the secondary wires secured so you can test them. That's eight wires flopping around. They gotta be held down some how or you are going to get sparks. I crimped on "U" fittings and screwed them all down to a terminal strip. Nice and tidy. No sparks. Also there should be some natural order to the leads. I had red leads on both sides of one secondary and blue on the other. Not good 'cause you don't know which end is up so to speak. But I lined them up red red blue blue red red blue blue.

Now you can start testing the voltages. First use a test lead to join two logical leads together. This would be one lead from each secondary. This leaves one lead from each secondary open. I picked a red and a blue and started there.

Then test between the two open leads. If the voltage is zero you are good. This is parallel wiring. If it is double the rated output of the secondary you have them in series. Change the lead you used from the first winding to the other lead on the second winding and check it again. When you get it arranged correctly the test will show zero voltage and then you can join them.

Note, if you read voltage, you have a difference in energy and you will get current flowing between the two. Too much and bye, bye secondary windings.

When this is done, the voltage across the two sets of connected leads will be the rated voltage of the secondaries.

OK. so lets say you got the secondaries of Transformer 1 and 2 hooked up in parallel properly. Now connect one "side" of each set of secondaries to the other and stop. Now measure voltages again. You should get something close to zero when you find the right match. I got 13VAC. A little high.

I did my trusty "spark test" by touching a test lead real quick to see how much spark I got. Not hardly anything. The better idea is to use a fuse holder in there and see if the fuse blows or not. (Thanks to Grummy) I used a .5A fuse and it held. So the 13V was probably a squirely reading out of my digital meter.

Given the good spark test, I went ahead and hooked up the two sets of secondaries and let it rip. It worked. Later I tried the fuse test, it worked too. I'm good to go.

Did that make ANY sense at all?????

That's it for today. Pix later.

Best,
-jd

OK, new pix. Compare these to the original power supply pics and you'll notice one less relay. Also you might notice the wire wound resistor mounted near the filter caps and the absence of the old ceramic resistors on the circuit board.

The new schematic is also there.

The #2 pic is when I was testing the transformer hook up using a 100W bulb as a load.

The #4 pic is the terminal block for the secondaries. I know I have several of these and they don't look any different really. That's kinda the point. I had to be real careful. I finally wrote numbers on all the wires with a Sharpie.


Best,
-jd

Got one Gecko powered up! Yay! I quit for tonight. Tomorrow I will first try to get that axis to move under computer control before I hook up any additional motors.

The power supply is working fine so far. More tomorrow.
-jd

Still no joy, got wrapped up in updating software and figuring out where I was the last time I made them work. But the Gecko is holding the motor in place, so it's working. Now if I can just get some signals to it......

The PC doesn't seem to be talking with the Sound Logic break out board. I had this issue before, I can't recall the solution and my notes are crap of course.

-jd

It's a little disembowled yet and I have a long list of to dos, but I
cut metal under Mach 3 computer control tonight.

Just jogging, no G-Codes.

I resolved the Gecko problem with a better cable. The one I had was really a printer cable so I think it was missing some conductors or the wire gauge was too small. So I got a full conductor cable with 25ga wire. Once I could get Estop back to Mach3 I knew that was OK.

Next I ran into a problem with the VFD making line noise. I followed that with the O-Scope. What was going on was that the noise went onto the mains, then into the PC and then into the breakout board and then to the Geckos. The motors started jumping around and the drive faulted a lot. So much so that I could not get it to take commands from Mach 3.

All I need to do is get an EMI filter on the mains to the VFD and I should be set.

I don't have the EMI filter yet, but I plugged the PC into another
circuit and that cut down the noise a lot. No more jumping, no more
faults, it's all good!

If you can afford even a beater O-Scope like I have, it's worth it.
That really helped me get what was going on with the VFD noise issue.

It does about 50 ipm on the X axis with no faults. Which is plenty fast for me. I think I might be able to get it up into the 60s though. 75 would be quite dramatic for me.

So thanks to everyone who has supplied help and advice, even if I did
get pig headed and do it some other way. It all helped and most of
all helped keep me going. Seriously folks, thanks.

For anyone wondering here's the basic stuff recap.

1980 - 82 Bridgeport 2J head, 9x48 table
Rockford rolled ball screw kit
Reliance Micro 100 Servo Motors (e-Bay)
Gecko G320 Drives
Sound Logic Break Out Board
Dell P3 Class Mini Tower Server
Leeson VFD
Home brew power supply
Home brew X-Y-Z mechanicals
Surplus cabinet from Young's Surplus
Surplus lights and switches found in the cabinet!
Turbo Cad 10
Soon to be purchased Visual Mill, probably from Bob C.
A load of wire
A mess of screws, nuts, & bolts
Spit, chewing gum, and electrical tape

Best,
-jd

1.) The machine prior to the final control hook ups. You can see the test leads wrapped around the motors. These were used to power up the motors with a test supply & check out the mechanicals.

2.) The chaos that is my shop. It looks worse at the moment.

3.) One new Gecko G320 mounted. Note that heat conductive grease has been used. Might be overkill and man is that stuff messy!

4.) All three G320s mounted. Note that the header blocks have been removed to expose the screws. I used 6 x 32 x 3/8 screws. The plate was drilled and tapped.

5.) The other side of the board with the Sound Logic board remounted and with my new $2.00 heat sinks I found at the local electronics store. In the surplus section. JK Electronics in Westminster CA. Nice, clean, neat shop. Most of them are just a nightmare of junk heaps it seems like.

6.) Noise on the scope. V/Div set to .1 on the 10x probe. That seems to indicate about a 5V spike on that shot.

7.) Same noise but at the setting of 10 - 15 V. So, that is showing us spike of about 10V. This is at the step terminal on the Sound Logic Board with the board and PC powered up. These are real short spikes. The time is cranked all the way down on my Tek 2213 scope. Makes sense the jumpy motor thing was real intermitent. It only moved the shaft 5 - 10 degrees.

My scope could be a little off too. It's a beater for sure.......... :o

So....Ordered an EMI filter. I wanted a new unit and I figured that was the most direct path.

It is lost somewhere in the UPS system in Los Angeles. I'll probably get it tommorrow.

So, back to Orvac electronics. No EMI filters but they had a slew of ferrite beads for cords. $1.95 each. Got a bunch of them.

Put them on both ends of the PC power cord, on both ends of the AC cord going to the Sound Logic Board, and on both ends of the cord to the power strip that is in the control cabinet.

Fixed! X-Y & Z motors all jog fine with the spindle on. No jittering while idle. Haven't scoped it yet to see the change.

KISS strikes again.

I'll probably still put in the EMI filter to get the noise off the mains.

Whoever suggested the ferrite beads, thanks very much!

Conclusions:

You CAN have your VFD 1 inch from your PC and 4 inches from your breakout board and motor drives IF everything is shielded and something is done to control the noise on the mains.

You can make shielding that is functional enough out of foil covered with heat shrink.

Liquid tight conduit with the metal in the jacket seems to work OK as a shield as well.

You can run your encoder wire with your DC motor wires in the same conduit as long as the encoder wires are shielded.

With all the wire properly shielded the VFD still sends a ton of noise out into the mains. This then will propagate through your system via anything connected to the mains.

Ferrite beads are in fact effective at soaking up the noise when located on the power cords to the other devices running off the same main circuit.

Best,
-jd

Keywords: VFD main gecko g320 g340 servo motor ferrite beads EMI conduit sheild

OBTW - The power wires in the coduit are also shielded. Key point. It has also been pointed out to me that this is NOT the normal convention. People usually run them seperate.

I took the chance as I usually see them seperated but in practice, tied up together and / or running very close to one another. So they may as well be in the same conduit.

-jd

A great thread. Keep it up! You are my hero.

Eric

Good to see you are once again making progress JD, hope the back is sorted now. Sorry I havent replied before but been kind of busy with the new project ;)
Series 1 retro
http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/Series1Retro.htm

Hood

Hood, Yeah, my back is coming along. Thanks for remembering!

Is that not a Series II machine? Nice tape drive! You can play old Stones reel to reel on it maybe? :-)

Best,
-jd

Balsaman - Thanks! I don't get to be a hero, ever!

Best,
-jd

Glad the backs on the mend, nothing worse.
Its a series 1 CNC Rigid Ram. Its more or less the same size as a manual series 1, the series 2 are a lot bigger.
Now why didnt I think of that, should have kept the tape reader in place and had a machine to music feature ;)
Hood

Thought I'd post a few notes on getting the screws off the machine so I could crank up the pre-load now that they are worn in some.

I'm sure there's an easier way to do this, but this worked for me. Most folks have taken the whole table off. At first look this appears to be the only way. That's what I did the first time too. Upon reassembly I realized that this was not totally necesary.

What I did this time was to first crank the table about half the way to the right. Also bring the saddle all the way forward.

Then I chained the table to an overhead beam to be safe. The other way is to get something under it. Couple of tall, really sturdy, saw horses. This thing is too heavy for two average, slightly overweight middle aged guys to be lifting. I bet it's 300 - 400 lbs. I used two roller stands and my chain hoist.

Then unbolt the whole bearing / crank assembly off the end of the screw.

Now you can push the table over until it clears the yoke and all four bolts are exposed. It binds up the farther out you get it. To avoid this use the knee lift to adjust it so the saw horses or whatever are taking some of the load.

It takes a pretty good shove. You could rig up something with a bottle jack too. That would be slower and safer. If you are using a come along or a hoist from above, you'll have to adjust it as you slide it out to the right. Move the table a little, adjust, move, adjust, etc....

So now you can get at the four bolts holding the yoke down. Take them out.

Then you should be able to slide the chip covers on the Y axis forward so you can reach in under the yoke. This should allow you access to the bold holding the Y-Screw in. You can also come up from underneath. That's hard because of the knee screw, but it helps.

Once you unbolt the Y-screw and if the saddle is all the way forward, you should be able to snake it outta there. Once that is done unbolting the x-screw is easy.

Here are some pics of the control cabinet. The first few are the air intakes. I positined these so the air is pulled right onto the Geckos. I've got an 8 in. fan on the other side of the cabinet so that drags air across all the components. There are also some misc. holes in the bottom of the cabinet that I never plugged. So there is a good deal of air circulating around in there.

Oh, you can see one of the ferrite beads I added to the power supply wire to the PC. White with the green tag on it. Snaps on. $1.99 or so. If you look next to the Leeson VFD, the noise maker in question, you can see another one on the power cord going to the 120v gear. It's a gray one and more rounded.

Now where is the EMI filter that I just got going to go........?

There's a program that comes with Mach 3 that draws a funky Road Runner. Like from the cartoon. I think the feet are too big. But, it's a good test on the machine.

So the point here is to put a pen in the spindle and draw something with the machine.

After you look at the code you can see one of the first things it wants to do is go to home, go out to a point, drop down .20 to make a mark presumably lift up and then go to it's starting point and start the shape. Again at .20 deep.

So to avoid a "Sharpie Crash" you have to set the zero Z position .20 above the surface. I did this by jogging the pen down unitl it just had some pressure on it. Then I pulled it up .20 and zeroed out Z.

Home is upper right for this one. So position your rig there. I think this is different for routers, not sure. Once you are at a good home, zero out the X and Y. Now if everything else is good it should run.

I had some problems 'cause the pen does not float and my testing surface was just a piece of flat cold rolled and it's not really too flat to begin with. So the pen came off in spots and dug in a couple spots. I destroyed the tips on 3 Sharpies before I got it right.

So let the program run as long as you have patience for, PULL UP the Z. Rewind the program and start it again. It should exactly retrace the line.

I then had to put the pen on an outrigger of sorts so I could start the spindle to see if the VFD noise thing had really been licked. It's working great so far.

See pics.

First is Sharpie in the spindle.

Next is a uniball type pen on the first pass.

Next is the same on the 2nd pass.

Last is the outrigger (Dial indicator stand) one the first pass. Spindle running.

Hi JD,

I/m retrofitting a 2J which is similar to yours.....Reliance on the X-Y,
MCG on the Z- all with Gecko Drives.
My progress is a bit slower because I'm also reworking a
a Boss 4 at the same time, which is easy & much less costly when
compared to the 2J . Enclosed are a couple of Pictures.....
Regards, Will T. Smith, Mission Viejo, CA.

Hi Will, Thanks for posting the pics. Looks like you are almost there with the mechanicals. I thought that was the hard part on mine.

I'm up in Huntington Beach. Nice to see another So. Cal. guy out there.

Best,
-jd

Back at it. Limits are the target sub project. Tomorrow I will drill and tap the left side of the saddle so I can build up the Y limit. The X limit only needs a spacer and will bolt up to the old X power feed stop mount point. The Z limit will be less of an issue since it's on my creation. I just hate punching holes in the stock machine.

Pics to follow.

Best,
-jd

So the first task as I saw it was to drill and tap some holes so I could actually attach a bar to the saddle to trip the Y-Limit switch. This is not a high stress part, but it needs to be firmly attached and strong enough so that it does not get knocked around. I'm going to use .325 thick alum. plate to do the job. These are extras I have lying about at the moment.

As I mentioned I HATE making holes in the machine. So I have been pondering how to do so without making a total mess. I could have taken the thing apart and drilled it with the saddle clamped to the ways, but I am not in the mood for that chore at the moment. So, I came up with a jig to secur my 1/2 inch drill to the table and use it as a horizontal drill press. See the first three pics below.

I have these milled angle irons I get at a local supply house. They are pretty square. So I bolted them back to back. Then I used the grip bracket on the drill to bolt the drill to the angles. You just unscrew the grip from the bracket on most 1/2 inch drills and you can use the bracket to mount the drill to something. This is the accesory grip that typically slides on the front of the drill. Then the angles were clamped to a piece of 1018 I have. I chucked a long socket extension in the drill and used that along with a square and a steel rule to get the drill aligned with one side of the 1018.

Now none of this is precision, but I'm just trying to get a hole that is within one or two degrees of being square.

Then the 1018 is clamped to the table using scraps for spacers until I get it to the right elevation. I used a twice folded piece of paper to get my last 1/32nd or so. Some tapping and tweaking to get it all lined up, then clamp it.

You can see the pic with the Sharpie marks. Not real precise but close enough for this. +/- .030 I think.

Measure it with a micrometer, mark it with a crayon, cut it with an axe??

So once the jig is set for the first hole a couple of blocks are clamped next to it so the second layout is faster. This at least preserves the alignment. The elevation has to be re done. Do that on both sides and it's done.

I used Mach3 in jog mode with the speed set at 1% of 50ipm to feed the drill into the work. Nice & smooth. I have a track ball mouse. With the cursor on the jog button this worked nicely as kind of a poor mans pendant. I just held the mouse in my hand and pushed the button to intiate the feed into the work. So even without a program loaded the control is already helping finish the work more easily and with better results.

These were then tapped to accept 1/4 20 bolts.

The last two pics are of the stock that will become the bracket and the cleat I mounted it to. I'm working on my first bit a real g-code now to cut that part.

Happy New Year!

Today was all about calibration. I have had to input corrections for the lead on each screw. I am not sure if this is right. If anyone out there has previous experience with this I would appreciate your input. It makes sense that the screw lead is not perfectly the same from screw to screw. However, I have had to make corrections of from 20 to 60 steps per inch on the screws in the Mach3 motor tuning section. Given 2000 steps per rev and around 30K steps per inch thats .07% to .2%. So that's 99.93% to 99.8% accurate? OK, I'll live...

A 23 year old machine that's 99.8% on the nose? Not bad I guess.

Repeatability is really, really great. It is at +/- .001 or better on all three axees. Which, with this old piece of iron sitting in my garage, is as good as it gets.

So, tomorrow I am going to try to write a program and cut an actual part.

Comments & suggestions are more than welcome.

Best,
-jd

I'll spare you all the gory g-code details. My first real honest to goodness CNC part is done. This is going to be part of my y-limit switch system. The attached pic has the first part on the left and the second copy on the right. They are exactly the same. At least to my eyes and fingers.

So, tomorrow I am going to try to write a program and cut an actual part.

And so you did, almost, wasn't the next day but ain't it sweet anyway :)

All that work is finally paying off, nice!


Ken

Hello guys, Im new to this site.
I lost my ez-trak software and I need a replacement for a:
EZ-TRAK SX machine
My reference book is titled:
EZ-TRAK SX
Programming & Operatioins Manual
september 1993
Bridgeport.
If you can give me any information I were I can obtain software please email me at cstrike62586@sbcglobal.net
thank you

Ken,
Thanks! Yes, it is sweet.

I got the part done last night. I did a 2nd, clean, copy today 'cause I goofed a little on the first one on the next to the last version of the code. Not fatal but you can see it very clearly. If I needed to I could make this part all day long! It's a really unbelievable thing to think one owns "the means of production".

Thanks again for the reply. I appreciate it very much. Makes the experience even better.

Best,
-jd

Hello guys, Im new to this site.
I lost my ez-trak software and I need a replacement for a:
EZ-TRAK SX machine
My reference book is titled:
EZ-TRAK SX
Programming & Operatioins Manual
september 1993
Bridgeport.
If you can give me any information I were I can obtain software please email me at cstrike62586@sbcglobal.net
thank you

David, you might want to start a new thread on your request. It might not get seen here.

-jd

Working Y-Limit assembly parts. These are the stops. I decided to hand write the code. Freemill and Meshcam both wanted to profile the part from a .stl file as if I were going at it with a ball end mill. I tried the Visual Mill Basic demo and it did the right thing. But I'm trying to hold off on laying down the $1000.00 for that. I really want the full version but it's $4K. Need to save up for that I am afraid. But it gives you four axes and some other bells & whistles.

So I wrote the code. It's in the zip file. The only snag was the cutter comp in Mach3. It works great but I did not know that if you use it in a subroutine that it needs to be "reinitialized" each time the sub is called. So the entry moves described in the Mach3 manual just need to be done again. The good news is that g3 is not required. A simple pair of G1s is fine. One will do it, but you want it to be done figuring things out before the part is engaged. Also, do that on exiting the part. If you stop on the last corner and then head off in a diagonal you get a little lip on the edge of the part.

Oh, this is using a .25 4 flute carbide end mill. The slot is 0.375. I wanted to see how well Mach3 handled the round ends of that slot. They are very clean. Actually I think this is a good way to go. Using a 0.375 end mill would probably result in some flaws at the ends of the pocket as the tool could pull into the work a little. I'll have to try that on the next one as a basis for comparison.

See Attached.

The first couple of pics are of the part before I got the entry moves right. You can see the angled cut on the left side. Then there are a couple of pics of it being done after the fix in the code.

The working code is in the .zip file. This is not perfect. Please pardon any style problems or bad coding conventions. If you have any suggestions on style & convention, please let me know.

You can see where I started using styrofoam to test with after the first alum part came out wrong. The lesson here is that you really need to run your program end to end on something that represents expendable material.

I once toured the Rockwell facility in Building 90 in El Segundo. They made the wing carry through box structure for the B1-B bomber there. They spent a tone of time testing the software for these giant parts on aluminum before they did the run on the real titanium stock. When the part was cut wrong they would bondo it back up, fix the software and cut it again. They'd be cutting the bondo the next time of course.

Then there is a Mach3 screen shot of when I had the code screwed up.

Today I'm going to try a little back yard heat treating. I need to take the stress out of that bar stock I'm using for those clamps. If I cut off that last .75 on the back of them they are going to warp. Going to wrap the parts in foil and cook 'em on the Weber for a couple hours. It's propane. It pegs the thermometer at 550 so I think maybe it's getting close to the 650 I need to soak the stress out of these. We'll see. Gotta start buying tool plate / cast alum remnants from now on.....

Thanks,

Can you with this cnc machine milling steel.

toneV8
Anything that a a manual Bridgeport can mill, can be milled with a CNC conversion. I often machine steel and also Stainless with mine.

JD
Looking great, nice to see you up and running.
Hood

ToneV8
heres a pic of one of the first things I milled, its the connector for the Z Axis ballscrew/quill. The cutter is a 20mm carbide.
Hood
http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/QuillConnector.jpg

toneV8:

Yep, no problem with steel. Bridgeports are pretty versatile. I am very vconfident that it can take .10 off with a .50 end mill. When I get a sharp .75 rougher I would like to try .375 out of some 1018 steel to see what happens. But I would say with sharp tools and the appropriate speeds and feeds it should be no problem.

As you can see Hood has done it. His machine is technically pretty close to mine I think.

Hood, thanks for the encouraging words as always. I guess you are about doing a Series II eh?

Best,
-jd

Got some work done today on the y-limit assembly.

The annealing effort I undertook last weekend on the Weber BBQ worked! The material is much softer, dents more easily and it did not distort as a result of having a slot cut in it and having a slot cut in the side of that slot.

Spent all week tweaking a program to surface off .75 the back of the part. It uses a couple of loops and some parameters that can be reset easily. So this is pretty re-usable. The only catch is that you have to make sure the step distances go into part size evenly. I might change the code so you set the number of passes and it calcs the step distances.

Now I need to re temper it. Soaking it at about 350 for 8 hours is supposed to do it. Then a water quench should toughen it up pretty good. Sometime this week maybe. I gotta buy a cheap toaster oven since I've been banned from the kitchen for heat treat work. Nuts! It gets to hot in there anyway...

Pictures are below. The program is attached too.

NOTE: Use the program at your own risk! Test, test, test! If it digs a hole in your table or anything else, NOT MY FAULT!

1 - Machining the part. Notice the the aluminum not chipping away clean. This is because of the annealing.
2 - Mach 3
3 - The part
4 - The assembly
5 - The part with the bolts in them

Here are the DXF files for the bracket and the stop. These were made in Turbo CAD 11. I had some conversion problems with it back in version 8 but I think those have all been resolved. These are 3-D files. There are also a couple of STL files in the ZIP file. That might help those using Free Mill or MeshCAM & such.

If you can't open them, let me know. I'll see if I can get my software to do something. They were created with 3D objects, so making them 2D is probably not going to happen, I'll just be honest there.

They are both missing holes for the screws & bolts. See the pictures above for that. I made the drawings so that I had all the dimensions to program the G-code with. I drilled on the mill drill so the hole dimensions weren't necesary. I didn't have a good idea of where the holes should end up anyway when I did the drawings.

Like I always say, use these at your own peril! Not that they are bad or anything. Just that my ideas in my little world here might not fit your application very well. But these are ideas that are free for the taking.

Hope it helps.

Best,
-jd

Nice progression, JD. I really like your write-ups. You aren't afraid to show your thought process.

Nice job - keep it coming!

Scott

Will do, thanks for the compliments. You too by the way.

-jd

JD, looking good :)
What type of switches are you going to use for the limits? (youve probably already said but I am to lazy to re read all through again LOL )
Its a series 1 BOSS that I am working on, wish it was a series II but well cant have everything ;) Its coming along fine, had some news about the new workshop and looks like I might be moving in two or three weeks so the Boss will be working soon I hope.
Hood

Well, I have two sets. One is a set of brand new Allen Bradley oil tight switches. The other is the swithces from Industrial Hobbies. I'm going to try the later first to see if they are as precise as advertised. If not, then I'll probably switch (heh..) to the ABs 'cause I think they are ultimately the most battle proven of the two. Less accurate but do I really care? It's a limit, not the real home for the work piece.

Best,
-jd

Well I can testify to the accuracy of the Industrial Hobbies ones, I did a test with them and homed approx 50 times and the most I was out between all of these times was +/- 0.005mm. I still have a DRO with glass scales on the mill and this was how I was able to measure, its resolution is 0.005 so the opticals are pretty accurate :) This is with my worn out ways so they are probably even better than that.
Hood

Excellent to hear! Well, I spoke with Aarron Moss at length one day when I ordered them. He's very into what he's doing. I am confident in them, which is really why I am going with them and not the ABs first. The ABs are now just back up. I'll use them for something...

.005 millimeters = 0.000196850394 inches. Impressive.

That's way more accurate than I can even hope to measure. My DRO stops at .0005 in. I guess I can eye ball .00025 ish on a gauge caliper.

-jd

JD, one thing I thought bad about these limits, but probably just because I am a rough bas***d is that the wires are easily pulled off of the circuit board. What I ended up doing is putting a cable tie (zip tie?) round the cable inside and as an added safety some epoxy in the hose tail so that the wire could not move. One thing I will say about Aarron is he is a very helpful guy, when I pulled the wires off I mailed him to see if I could buy a new optical switch if I screwed it up when re soldering, he offered to send one free. In the end I managed to prise off the optical, re-solder and then glue back in place so it wasn't needed but it was a very nice gesture and makes you feel confident in the guy and his product.
Hood

Hood, great tip. I will make sure I do something to secure those wires. I tend to abuse things as well. Yeah, I think Aarron is a top notch guy too.

Best,
-jd

Some JPGs of how this is going to come together. With any luck it'll be done tomorrow.

So the first thing was to anneal the alum parts in the Weber with some
tile stacked around them for a couple of hours. Trying to get to 650 to
700 deg F. Worked. Sounds dead. No ring. Soft. Dents with a smacked by
a screw driver handle.

Machined the part(s).

Now to make it hard again. Oh baby!

Got a $19.00 toaster oven at Target and two different oven
thermometers. Eyeballed the temp average at 350. Bake for 8 hours. Drop
in a bucket of cold water.

The John Delaney hardness scale is a 5. 2 was when I hit it with a
screwdriver handle, it dented. 5 means it doesn't.

It won't be finding a home on s 777 anytime at all. But it's harder
than it was. I'm thrilled I got it to work at all.

The mechanicals anyway. Hood, if you read this, what's the deal with the wires? Do they just get stuck in the holes? No soldering I assume.

So here are the pics:

1. - The rig I used to try to help keep me drilling straight when I punched the first hole in the knee.

2. - The block bolted to the knee to help as a guide. Well it worked OK. Both the holes are a little catty wumpus but close enough.

3. - The holes after tapping. BTW - I did that with the tap chucked into my 1/2 inch Milwaukee Hole Shooter. I love that drill! I tried hand tapping it. What a joke that was. Couldn't get it started worth beans.

Then there are some pics of it all bolted up.

Then a heat treat pic. This is the $18.95 toaster oven. Call it $20. Then there are the two oven thermometers with wildly different readings! 50 degrees or more off! Nice. No wonder the turkey gets dried out!

Then the whole frigin mess. I haven't posted one of these since the table was taken off and put back on.

OK, I think that's all in order. If not, shoot me.

So...this was the hardest assembly next to the Z-Drive. What made it hard was that everything is kinda floating in space over there. There are no really good places to measure from either. I HAD to put this in 3D CAD. I just could not make it work with sketches. There are also three moving or moveable parts. The two stops and the bar they clamp on to. Then there was the considerations of what the limits would really end up being.

I had to be able to adjust the stops to allow for a vise mounted on the table, but if it was not there I wanted max travel of course. Then the question of not having it hang out into the walk way made it a little harder.

I had to scoot my control cabinet over about an inch to accomodate the bar. Thank God I put it on Unistrut.

The there was the whole heat treat thing. Then there was drilling six holes in the machine. Man I hate that!

Anyway, I'm tired and relieved to have this one done. Onto the Z-Limit.

Best,
-jd

John, you are a life saver! I am about to embark on this project for myself. I have read each and every post that is in the thread. This has helped me with a lot of my questions. I can only hope that my project turns out as well as yours. Information like this is price-less. Thanks for all your indepth posts. This is my favorite thread on this entire site. I hope that more people can see the value and be as indepth as you have to help others. Keep up the good work and post some more pics of parts that you have programed and machined. Bryan Berry
www.bryschopper@aol.com

Very glad to hear it is helping. Have some fun with your conversion. Keep us posted if you can. Thanks for the good words and encouragement too. Helps keep me going.

----------------------------------------------------------------------------

Posting a couple more views and the DXF file for the y-Limt.

This DXF is what I cut and drilled the parts to. It is 3D again. Sorry to the 2D folks. Hopefully the .JPGs are of some help.

Had to zip the DXF. Too big.

Best,
-jd

WARNING:
As always, use of the ideas, drawings, schematics, plans or any material on this thread is at your own risk. These are intended for people with some experience in this area of work. If you are a total beginner, this is not for you. These are powerful machines and can cause all kinds of injuries or DEATH.

Sorry, just have to say that so someone doesn't freak out on me. If you are a total beginner, I am glad to help you along, of course.

JD not sure what you are meaning when you say "what's the deal with the wires? Do they just get stuck in the holes? No soldering I assume."
Hood

Sorry. On the limit switches. You mentioned that the wires come out of the little tiny circuit board on the back of the sensor. Sure enough, one of my wires came out on one of the switches. I stuck it back in. Popped out again. So...I'm going to try your tie wrap idea. Also I was thinking I could stick a piece of foam in there to hold the wires against the sensor which should keep the exposed end from poping out of the hole.

Anyway, I did not see any solder and I did not see a way to get that circuit board off the sensor housing either. Maybe is pulls off?

Best,
-jd

Hood, so now I just re read your post. Duh on me! There is solder. OK. Hmmm. Need to examine this one a little.

-jd

AHHHHHHHHHHHHHHHH I was afraid that was what you meant.
The wires are indeed soldered onto the board, you will need to carefully prise the optical switch away from the Aluminium case as it is glued with epoxy, once removed then you can solder the wires back on. Stupidly I did not take a note of what colours go where so you may have to do like I was forced to and remove a switch from another just to see the wire locations. It might be worth calling Aarron and seeing if he can tell you where they go.
hood

Hood, OK, thanks. I'll take a look once I get the mechanicals done. I only have one loose right now. I might be able to solder it without taking the sensor out of the case actually.

Best,
-jd

Got the drawing done anyway. So tomorrow will be programming and maybe some part cutting. Maybe.

Edit (01-27-3006)

I think this is the most specific set of drawings I have loaded so far. I want to caution anyone using them on a few things.

1.- The dimensions on this entire z-assembly are driven byt the screw I selected. I picked a Rockford Y-Axis screw from one of their Bridgeport retro fit kits. I did this because I wanted identical screws all the way around. Not necesary. It has developed into what I think is an over sized drive. The up-side is that the beefy screw is helping with some of of the "link rotation" I'll call it. The stated problem is that these bolt on X-drives tend to get flexy due to the screw being too far from the quill. In practice this does not seem to be a problem for me so far.

The screw is like 1.16 dia at the tops of the groves. It has been heavily modified from the original. It is shorter. A bearing journal has been added to one end. The other end has been tapped to accept a thrust bolt.

2. - The trip plate, as I am calling it, is again sized for these screws. I am also using .313 alum plate 'cause it is what I have. No magic there. I buy bits and remnants at IMS and make do. Some things are too big, some too small as a result. Usually too big as that's my tendency. Must be compensating for something...

3. - I have been told that Bridgeports do vary some in several dimensions. Castings shrink differently and there have been minor design changes over the years. Mine is a 1982 vintage machine. So the universality of any dimension is seriously questionable.

4. - I am seriously winging it here. So far so good though.

5. - The DXF is sans the z-drive frame. If you read up the thread I had a little patent disagreement with someone. We agreed that this design does not infringe on his patent, but I also agreed not to post a DXF of the drive as built out of respect for his business position. We both agreed that thers is enough information in the thread now to give someone with skills and motivation to pull it off. So, this is as much as I am going to publish regarding this version of the Z drive. If I decide to do more I will place another call and revise the understanding before I do.

There are two standing patents on Z-Drive retro fits. Both of them are very narrow as one would expect. This is a relatively old line of work and most everything has been done. Not much has been patented. So a lot of stuff is public domain I suspect.

Best,
-jd

WARNING - Use of these drawings is at your own risk. I routinely find problems with them once I get down to the shop. I make NO representation that these will work on your machine. These are intended for people who are well experienced in this area of work. OK? OK.

Drawing revision note - The 0.625 holes for the rod are probably going to be sized up to 0.6406 (41/64) or 0.6563 (21/32) depending on what drill bit I can find at OSH tomorrow. Unless of course they don't have 5/8 drill rod. In which case I will go with iron rod and turn it down to 0.620 or so....

Got the mount blocks for the rod done today. Will probably have to re-drill them as mentioned.

Having backlash issues. Going to have to stop and get that right. I keep guessing at it. Hasn't been a problem, but this assembly is going to have fit problems if I don't be careful.

Still getting used to the manual data input (MDI). Almost took a notch out of the Kurt today. Good thing that was a g1 and not a g0!

Best,
-jd

SAFETY ITEM - I've again been reminded that running the encoder wires in with the motor power wires is potentially risky and could cause a feed back problem on a servo motor set up.

Backlash update.

Just got done adjusting the backlash settings in Mach3. They are:

X - .0138
Y - .015
Z - .0032

I was losing .002 on X on some of my parts. That's about what I adjusted into it. I forgot to write down the before numbers. :-( These numbers seem high to me for ball screws. But I can't ever seem to get anyone to give up what their back lash numbers are. Not sure if everyone is shy or what the deal is.

My bet is that the Z number will change. The Z screw has the least wear on it.

If these numbers continue to get worse then I'm going to have to replace the balls and then eventually the whole screw kit. Fun! We'll see.

Best,
-jd

JD I am not sure what the backlash on mine is, I have never really accurately measured it as the ways are badly worn so that will add a bit to the readings. I am working away from the workshop today but Tuesday or Wednesday I will try and remember to measure to see what I have. I thought you had new ball screws so am surprised you have backlash at all, but maybe thinking of someone else. Mine were all off eBay and were hacked and machined to suit.
Hood

Hood, thanks for checking. I am very interested to see what the norms are. I've decided there is no such thing as "zero" backlash.

I decided something must be wrong with those numbers. The tip was when I went to actually position something this morning it over shot the mark by quite a bit. visible problem.

So, I disasembled the Z-Drive and retorqued the quill bolt to 60 ft. lbs. It was loose, maybe had 2 ft lbs on it when I loosened. Put some blue lock-tite on it this time too.

Then I torqued the thrust bearing to 10 ft lbs.

Then I re-torqued the Y thrust bearing to 10 ft lbs.

I had recently done Z cause I removed the crank handle so that's under control. I think..... :rolleyes:

Then I re-measured using an analog dial indicator instead of a digital caliper.

New backlash values:

x = .0012
y = .00135
z = .0042

I think I measured something wrong on X yesterday or something. Not sure.

Well, going to make some parts today, so we'll see.

-jd

Should be at the shop tomorrow so if I remember and its a big IF ;) I will measure for you.
Now back to my probe design, mark IV so far LOL
Hood

Hood, no problem. If you get 'round to it, great, if not that's cool too. Probe eh? This should be interesting.

-----

Well, so far today it's behaving better. I made a couple of interesting discoveries. One, if you are slotting with a skinny end mill, say .25 there's a lot of wobble. I lost at least .002 - .005 on a part due to what I am guessing is just the chips swirling around in the coolant and knocking the bit out of it's path. When I made the cut on the end of the stock, the results were much better. So, that's an interesting thing.

Also if one sets the zero datum for Y on the fixed jaw of the vice, the day goes much better. Same for X. So that means at least all your Y points are in the negative numbers. I also played around with a "ghetto material stop". I stacked up a bunch of scraps and put my V-Block on that. Then a 5/8 rod was clamped in that. The whole stack was clamped to the the table. The rod made a good material stop for repetitive operations. It also became my zero line for X. Having to reset your datum on low precision parts is just irritating and pointless.

Best,
-jd

JD I actualy remembered to measure the backlash
X = 0.075mm (0.00295")
Y = 0.080mm (0.00315")
Z = 0.045mm (0.00177")

The funny thing is that the only screw that was supposed to be new was the Y axis and that has the greatest backlash. However I think it may have more to do with the amount of play in the ways more than anything, with the gibs fully tightened I still have a lot of slop and the Y is the worst.
The probe is coming along OK but think I will have to wait until I get the BOSS on the go before I can make one capable of being used as an edge finder. So far it could be used for digitising as really it doesnt matter if the ball is off spindle centre but as there is about 7 thou runout it is no use as an edge finder. I have an idea of how to improve on this so maybe Mk V will be the one ;)

Hood

Thank you VERY much. BTW - someone over at DIY-CNC suggested the .003 backlash is normal for 5/8 rolled screws from Thomson Saginaw. So, it looks like we are both in a reasonable range.

Good luck with the probe. Sounds like that will make locating your work piece easier and faster.

Best,
-jd

...
The probe is coming along OK but think I will have to wait until I get the BOSS on the go before I can make one capable of being used as an edge finder. So far it could be used for digitising as really it doesnt matter if the ball is off spindle centre but as there is about 7 thou runout it is no use as an edge finder. I have an idea of how to improve on this so maybe Mk V will be the one ;)

Hood

I've been looking a making a probe and have a thought or two on making the ball concentric with the spindle. The ball is some distance from the probe itself, so any small error in the alignment of the threaded hole holding the ball probe will throw things off. That's lead me to the two following approaches.

The first is to just calibrate the error away. That requires that the probe be chucked (well, colletted) in the same orientation each time. Put a piece of precision rod in the collet and align it to a matching slip fit hole in a block on the table. Clamp (or better yet, use a magnet) the block to the table and set the location as zero. Now mount your probe in its fixed (rotational) position and probe the hole. Any value you get other than (zero, zero) represents the error. Now when you use the probe, just subtract that value from the location you get.

The second is to make the probe adjustable. I'm sure there are lot's of ways to do that. Most of them would require a fine pitch screw to dial out the error.

Let us know how you are doing on this. Some drawings would be nice. (hint, hint).

I believe I've come up with a way of making a probe that doesn't require that the rods be insulated from each other. (I'm assuming the use of a Renishaw style proble with three rods and six balls). Instead of completing a circuit connecting all six balls by passing current through the balls and rods in a serial circuit, I would ground the rods and check if any of the balls is not grounded. I believe this can be done with a simple circuit consisting of diodes and resistors.

Ken

I have had some sucess but only some, I have to go out for a while and will elaborate later but in the mean time heres a pic as requested.
Hood
http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/Probe.jpg
http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/Probe1.jpg
http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/Probe2.jpg

Ken I was thinking along the same lines as you regarding finding the errors in probe and subtracting but then I decided it would not be that great. The reasoning I have for saying that is if I was trying to edge find on a circle then if I was not spot on an axis the part of the ball that would be touching would almost be impossible to determine and thus allow for the error. Granted this may be a very small error in calibration but it would be there. Secondly getting the probe in exacly the same orientation in the spindle and holding it there might be hard to do.
As you can possibly see from my drawing I have setscrew holes in the side of the holder so that I can adjust for alignment and this will be my next step.
What I did today was make up a new rod holder and assemble the probe, I then put a setscrew in the top hole and screwed it in so that the pins were held tightly against the balls and there was no way for any movement. I then mounted the probe in the lathe and faced off the front of the stylus holder and drilled and tapped it, I still have and error though :( although it is down to 2 thou now, hoping the adjustment screws will allow me to dial that out, I would be happy with a few tenths :)
Your idea of grounding the rods sounds interesting, if you go this route be sure to let me in on any info.
Hood

[JD -- we'll return the thread to you shortly...]

Ball diameters, rod diameters, distance from balls to the center, center to center ball diameter.

I assume that you want the rods to sit on the balls so that the three centers form an equilateral triangle -- more or less.

I'd be concerned that the adjustment screws have too much range rather than too little. I'd use a 40 pitch screw -- even then, it doesn't take much motion for a thousandth of an inch. Just look at a micrometer.

It looks like your adjustment screws press against metal. I think that's the right idea.

Ken

Hey, no problem. You guys can hijack my thread anytime! Actually the probe thing is pretty interesting. I'm getting tired of locating the local home by "hand" if you will.

So anyway back to the regularly scheduled update.

Today we milled foam! Good thing too. I found a problem with the trip plate fitting up to the ball nut. I was also trying out some of the canned cycles for drilling (g83) and doing some more radius work (g2). I also played around with tool changing (m6) so I can change the drill bit size in the drilling program. I split the drilling program and the milling program since there is a big setup change between the two.

The Mach3 Tool Path window is excellent for checking it all out before you start cutting parts too. I've copied the .XML config file to my CAD PC. I do my coding there and once it looks good on that machine I copy it over to the control PC and head down to the garage.

So anyway the code looks good and the practice parts fit.

I tried making some 5/16 holes with a 1/4 end mill using g12. Came out pretty good.

The first couple are of the front plate and the last one is of the front plate taped on the machine. That was before I shot some black paint on the foam so I could see what was going on better. You can see the trip assembly sitting on it. This allowed me to verify the hole locations too.

The next are of the trip plate. That last one of those, I think, is it being fit in the machine.

Best,
-jd

JD thanks for allowing the HiJack :)
Agree whole heartedly with your comment about the Mach window, I use it all the time. Set up my material, jog to where X0 Y0 will be and zeroDRO then jog to extremeties of the part on screen and check no clamps etc will be in the road of the tool. Also very handy is the table view option.

Ken
The adjusting screws are not present in the above pics, the cap screws you see are for holding the two halves of the probe together, also have another three through the steel holder which hold the probe in place. The holes on the side of the steel holder are where I have the adjusting screws (see new pic), they are pointed socket setscrews and bear against the Acetal body of the probe. The only ones I have are too long so will need to be replaced with properly sized ones but for now they will suffice. If I make a mark V I will probably have Acetal inserts in a steel probe so the adjusting screws would be bearing on the steel body, time will tell if the probe can stay accurate the way it is now.

Well had some time to mess with the probe today and within 10 or 15 mins I had it set up to within 5micron :) My adjusting procedure was simple (like me ;) )
1. Set up in the spindle and check runout, less than 0.0001" so I was happy
2. Had a LED connected to the probe so that I could see when contact was broken.
3. Orientated so one of the four adjusting screws was facing me
4. Brought the probe up to the edge of the table until the LED went out, changed to step mode (from Velocity) and moved until LED was again lit. zeroed my glass scale DRO and repeated a few times. I found I could repeat to less than 5micron (smallest my glass scale DRO can read)
5. Backed off and rotated 180degrees and repeated step 4 and noted difference moved halfway and adjusted screws so that LED was out.
6. Repeated procedure on other two adjusting screws
7. Repeated whole procedure again from 4 to 6

Wound up with under 5um as stated above, ie my DRO always read 0.000mm as the LED went out, i turned the spindle to many positions and each time my DRO read the same so I am very happy with that. I dont know exactly how accurate it is but under 5um is good enough for me.
Next step will be to measure exactly what diameter my ball will be, ie ball diameter plus distance required to break contact, should be able to do this by setting up a mic on the table and jogging the probe between the faces, subtracting distance travelled from the mic reading and dividing by two should give me centre of probe I think :rolleyes: .
Below is pic with LED setup and (far too long) setscrews, BTW they are M5 x .8 which is not too far away from your recomended 40TPI and they were fine enough thread for easy adjustment.

Hood

http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/Probe3.jpg

In an attempt to unhijack the thread, I've posted the following:

http://www.cnczone.com/forums/showthread.php?t=17145

Hood: sounds great. Now if I could get you to post some dimensions: rod diameter, ball diameter, distance between the balls of each pair, radius of circle thru ball centers, I'd start copying your design. -- And modifying it to use my new logic system.

Ken

Dare I say that I think this is the last of the mechanical parts to be made.

This one was relatively easy except for the machien doing something odd on me once. But a restart seemed to have fixed it. The series of four parts shows the problem. On the foam cut it simply did not move far enough on the G0 to a new X position. Then it did it again later. It is possible that both times I left the vise handle on and it jammed the travel. Anyway it came out OK in the end.

OBTW - 3/16 two flute end mills suck for eating your way through .644 of alum plate. At least HSS. Maybe cobalt or carbide. The HSS was too flexible to hold a good cut.

Here are some pics of the stuff.

I am now hooking up the electronics for the home & limits. Hope to be done tomorrow.

Best,
-jd

JD i regularily use 4mm two flutes for 5083 Alu and they work great with no visible flex but they are carbide so possibly that is the difference. Also 5083 is a nice Alu to cut, its not claggy like some other grades and best of all I have lots of scrap bits as its a marine grade and what I use all the time when welding up masts, shelter, fish hoppers etc for the fishing boats.

Found a problem with my Y axis yesterday, the pulley was a tiny bit slack on the key, put a setscrew in today and remeasured the backlash, 0.005mm which is about 0.0002" :) shame the X is out so much and also that the ways on this mill are shot. It wont matter soon anyway as I should have the BOSS up and running in a week or two and I am hopeful that the ballscrews on it are in as good condition as its ways.

Hood

Hood, thanks for the suggestion and insight on the tooling & materials. Interesting that you are doing marine work. I used to work on a boat when I was in college. Paint & varnish & mechanical as needed. Jack of all trades stuff as the crew needs to be at times. Good times. I love boats.

So....The past couple of days has been consumed by how to do an e-stop safely. I work alone a lot. I want to be sure that when I hit one of two or three Big Red Buttons (BRBs) that everything stops, like now. Fortunately the machine has enough friction in the ways that it doesn't coast. I do need to test killing the power in the middle of a rapid to see what does happen though. I may want braking resistors on the DC drive motors. But I don't think I need them.

Any suggestions would be welcome.

After some poking around I think I am going to make a circuit that will kind of unify the Gecko err pin, the e-Stop feature on the Sould Logic Board (SLB), the DC power supply, the VFD, and the E-Stop loop. I have a very complex circuit sketched out that I am trying to reduce to a more elegant solution.

Also I am going to build a spring loaded brake acutuator with a pneumatic unloader. Killing the power with the E-stop will relieve the air cylinder and the spring will engage the mechanical spindle brake. I may have to go double acting on the brake to get enough force. That's a lot of spring if I don't.

Then I need a pressure switch in the E-Stop loop.....This just goes on and on...

I thought about this. At first I figured that it only takes the spindle 2 - 4 seconds to stop once the power is shut off. That's freewheeling. If it was cutting it would be less of course. Then I thought with something like a fly cutter, that could be a lot of time and a lot of injury or damage to the machine.

I've seen these on Bridgeports. Usually associated with automatic draw bars, but I have seen some solo. The other plus is that I will be able to use it when changing tools.

Anyway, that's what's going on this week.

Best,
-jd

JD
The BOSS mills have air brakes (well most of them) just a double acting cylinder. Very simple and very easy to control. They use a solenoid valve, not sure exactly what you would call it but air flows through one way when not activated and the other when the solonoid is powered, so I suppose a diverter would be a suitable name. The air activates the brake when NO power is to the solenoid and when power is applied the brake is released, this makes it simple to connect through a BRB as you call them. Mine is wired a bit differently in that my E Stop completes a circuit for my main contactor which controls just about all things electrical on the BOSS. So if the E-Stop is hit it kills the power to the contactors which in turn kills the power to spindle, brake solonoid, lube etc
The E-Stop is also connected to the PMDX breakout so that it also lets MACH know that the E-Stop is hit.
Hood

EDIT
Also have an over ride switch so that I can release the brake when spindle is stationary.

Hood, cool. I've ordered a double acting air cylinder, a 4-way solenoid valve, regulator / filter, and a lubricator. I need to get a switch too. The whole lot was $97.00 at surplus center. That place rocks. Based on what you are saying and what I think I have seen I don't need a spring or anything. Having the pressure switch to lock out the system when there is no air will cover the no air possibility.

Once it's all here I can get back to the E-Stop project.

Hey, those limits are great. Saved a minor crash today! It also making tool changes faster as I just have to run Z up to the limit and then wrench on the draw bar.

I appreciate the confirmation that I'm going the right direction. While I'm waiting for that stuff to arrive, I'm back to the CAD for my product.

Got the qoutes on some 6061-T651 today and it amounts to $30 - $40 per part. OUCH. At that rate it'll retail at $150.00. Aluminum prices have really gone up.

So....if I am every going to get this to market I am going to have to get it extruded or die cast. So I need some better drawings so I can get some decent die casting and extruding qoutes. I also need to design in draft, fillets, etc. for the casting folks. The extruders won't care. All they need is a section.

Best,
-jd

JD, Hood
I'd be interested in what you think about a couple of products listed on Ajaxcnc.com.
listed under "cnc components".
1) Full Wave Bridge Rectifier PC Board assy @$29.
2) Z axis optical limit switch assy. @$59.
I particularly like 2) because it mounts on the inside the
z axis assy & takes up so little room.
Regards....Will Smith

Will:

They look pretty good to me. Nicely made. The parts all look right.

The negative temperature coefficient thermistors are seem to be very common for in rush limiting. I did not use

I do have a cocern about the bleeder resistor. It has to have more resistance than your load. But, as long as your load has a lower resistance it will be 100% OK. Just check this out. If your load has a higher resistance, then the resistor will see more current and might get hot if that current is too much.

There are about $10.00 worth of parts there. It's a fair price for what you are getting I think.

The limits could be real useful. Are they supposed to go inside a Boss head on a Series II machine or one like Hoods got or...??? Not sure.

You need to get the dimensions. From the looks of them they will barely fit inside my Z drive and mine is pretty big. The design of their placement and whatever you use to trip them could be tricky. But I think they could work real well. You have to make sure they are protected from chips & coolant of course.

Maybe they are for the Elrod quill drive. I see that unit on one of their conversions.

Best,
-jd

Will,
Not looked at the AjaxCNC stuff yet but will reply about the optical switch first anyway LOL
for the Z Axis on the manual conversion I just have a slotted optical switch. I found that there is no chance of contamination by coolant or chips up there so it was ideal and only cost £3 or £4, you guys in the US will probably get it for the same in $$$. All that is needed is to fix it to the ballnut and have a plate in between to break the light. Oh you allso need a 220 Ohm resistor .
Below is a pic of the setup.
I was going to use the same on the BOSS but as there is a lot of oil inside the quill housing I decided to make an enclosure for the switch similar to the Industrial hobbies ones but it had to be smaller in height or I would have just used one as I had a spare.
Hood

http://mysite.wanadoo-members.co.uk/hoodsmachiningpages/OpticalSwitch.jpg

JD & Hood,
I taped the limit switches to my Z axis assy so you could visualize the scale.
I also rec'd my new Toroid Xfmr fri & have started the installation & hookup.
The BR board is installed on the CAP.(18000uF)
Hood, here is a pic of the Boss Head, I can remove the cover if it will help.
Will Smith

Thanks for the pics and the offer of removing the cover but I have found that I actually have a large drawing of the head that you have.
The limits look good in there, didnt realise you already had them when you were asking your question or I wouldnt have replied the way I did. You could have done exactly the same with one switch and a resistor but I suppose at that price its hardly worth the bother of making up the brackets etc. Just wish things in the UK were as cheap and readily available as you USA guy have.
Hood

Those limits are smaller than they looked. I think that's the right idea you've got going there.

So, do you have two conversions in progress?

-jd

JD,
Yes, 2 conversions in "Progress ???"
See Forum 16888 Notes 18,20,22 for various pictures of both.
This forum Note 104.
Regards,...........Will Smith, Mission Viejo, CA.

Will, you know anyone in the area or north up by me HB / Costa Mesa looking to split or sub-let some shop space?

I'd say you are making progress. Mine took way longer than I figured too. I figured, heck, three four months! Two years later.......

But it works.

-jd

I am just beginning a project to convert my Bridgeport Stepped pulley mill to CNC. Right now the table, saddle and knee are out being reground, squared and scraped. I just read through all your messages about your conversion. Where did you buy your Rockford ball screws and how much were they? I emailed Rockford and they replied that my request was forwarded to another person and I have never heard back.

I still need to find some servo motors. I know some about steppers, but nothing about servo's.

For the power supply, I was going to buy a 60VDC 25 amp one on eBay.

I plan on using the Gecko drives.

Any suggestions on the servo motors would be appreciated.

Vince

Vince,

I got mine from them. You gotta call. They are not as responsive via e-mail. I lived in that area for a little while. Business is still conducted person to person there. A town full of great machine and tool makers. So is Beloit WI which is up the road about 25 miles. But I digress.

Also they sell via McMaster Carr. But, I would make sure you have the right Rockford part numbers and ask for a discount. Worth a shot. Tell 'em you're looking at Hiwin instead...

Before you buy the power supply, I would suggest getting the motors figured out. Spend some time on CAD_CAM_EDM-DRO and DIY_CNC over on the Yahoo Groups and / or find some threads here on motor size calculations. At least get a feel for what's going on. Or if the PS is a sweet deal, go for it. What the heck.

Having said that, 60V at 25A gives you 1500VA, That sounds pretty good based on what I have seen over the past couple of years. If it's not you can add another, run one gecko off one and two off the other or something like that if you want. All kinds of frankenstein scenarios are possible. It just gets messy.

You DO NOT need matched motors by the way. Nor do you need matched encoders. Your software will allow that all to be adjusted. Well mine does. Mach3 and I think TurboCNC does as well. I know EMC does.

Get the motor voltage a little over the PS voltage. So if your call is 60V, I would suggest not going more than 65V or 70V on the motors. The higher the motor rating over the PS the slower the motor will run. With the Geckos you really should not run more than 75V anyway. I would say 70V. Marriss says they smoke at a volt over 80V. Remember that your mains fluctuate some.

So if you end up with three different motors, you might in fact want three different power supplies. The Geckos won't care 'cause all they see is their own little individual world of voltage, step, and direction. The only external thing it will see is the err signal.

My motors are 1/3 hp motors rated at ~ 100V. I am driving them at 56V. But you probably know that from my thread.

Also, you are going to see some folks popping off about NEMA 34 -vs- NEMA 42. NEMA 42s have a bigger frame size. It's about an inch bigger. That's it. If you get a longer NEMA 34 it can have the same performance as a shorter NEMA 42. So it depends on your physical design limits. Now there are some sanity checks here. You are unlikely to get a NEMA 14 frame to hold enough guts to run your X-Axis drive. Maybe the Z, Maybe.

While I'm on it about the Z-Drive. There is a really good case for a long skinny motor on that one. You want everything on that as close to the quill as you can. If you go with my concept I'd go with a 5/8 screw using a preloaded nut and get it right up close to the quill. Think in terms of minimizing all your lever arms in that assembly.

I am having no trouble with my design by the way. Works better than the manual machine ever did.

OK that was a long one. Sorry.

Best,
-jd

I have uploaded a picture of a mill with the Z (Quill) axes motor mounted to the side of the quill on the handle shaft. What is the down side of this?

The second picture is my mill in its present state. I purchased it 7 years ago for $500 sight unseen. My brother said it was in great shape with no slop in the table. It is an older mill and had zerk fittings instead of an oilier. Some rocket scientist saw those zerks and decided they were for grease. The reason everything was tight was it was plugged up with grease. I took it all apart and cleaned it and when I got it back together it was so loose I had to shim the gibs to take up all the slack, and even then if I adjusted it tight in the middle, it would not move toward the ends of travel. I finally found a guy locally who can regrind and scrape it and that’s where I am at.

Vince

I have uploaded a picture of a mill with the Z (Quill) axes motor mounted to the side of the quill on the handle shaft. What is the down side of this?
The quill drive via the handle is by rack and pinion and in every Bridgeport I have seen there is a considerable amount of slop. In a manual machine this is of no consequence but driving the quill that way for CNC would not be accurate at all, ie huge amounts of backlash and almost certainly very poor linear accuracy. I had considered doing things that way but decided ballscrew was the only way.
Hood

Hood nailed it. That picture looks like it's really a power feed and not a CNC. There's no encoder. Unless that's a stepper motor, which it could be.

That machine might just be for drilling too. Which is totally cool. Who cares if the hole is a little too deep or shallow most of the time. Also there would technically be no back lash needed as the direction of cutting pressure and feed is one way.

When you are milling it is both up and down. When you are feeding into stock vertically it's pushing back like when you are drilling. When you are moving horizontally it is pulling down due to the usual grind on the flutes. If you could get reverse ground tooling that would always push up, that would work. Not sure about that...hmm.

The back lash compensation in Mach3 anyway is one number. I bet that if you measured it the back lash on the rack is different with every tooth. So even if big backlash compensation was a good idea, you'd have some trouble getting it to be consistent over the entire travel of the quill.

Here's an interesting thought. But it's more work than it sounds. There might be a way to make a split pinion where the two halves can be sprung against each other to take up the back lash. The force would have to be in excess of the cutting pressure from your largest tool.

I've had a 3/4 rougher get pulled out of the collet into the work. There are some big forces at work with large tooling.

I don't know much about the guts of the head. Not sure if a big spring or some kind of pneumatic preload could be put in there to take out the back lash. You "just" need to to push the quill hard against the pinion at all times so it never loses contact with the rack teeth.

Typically this is deemed impractical I think.

Hope that helps,
-jd

OBTW - What's that regrind costing you. I'd like to do that sometime. Maybe.

Keep going man, great start.

-jd

$350 for the table, $100 for the saddle and $200 for the knee.

Can you recoment a link that details servo motors?

BTW, that is a stepper motor on the quill in the earlier picture.

Vince

Wow, that's cheaper than I thought.

I would suggest going over the Yahoo Groups. CAD_CAM_EDM_DRO and DIY_CNC have a lot of good stuff in there if you can dig it out.

http://groups.yahoo.com/group/DIY-CNC/

http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/

I use an application called PG Offline to gather them all up locally and make them searchable. There are some good links there too.

It's a stepper? Any idea what they are doing to take care of the backlash? If they have a good solution it would be good to know about. That would sure be a lot easier.

Thanks,
-jd

I belong to both groups. I am slowly gaining a better understanding of servo motors. I have my transformer now and some caps, I think I have a bridge rectifier as well. I may have even found three nice DC servo motors. The guy selling them did not know anything about them. I tracked down the manufacturer and they are supposed to email me the specs. They look to be between 1/4 and 1/3 HP.

The guy with the stepper on the quill is Bryan Mumford. He did his conversion in 1999. He does mostly wood with his mill. His website is:
http://www.bmumford.com/cncmill/index.html


Vince

The motor part of the servo motor is nothing really special. It's a pretty normal DC motor. In fact in my hobby robotics research a lot of people are using whatever DC motor they can get and making their own opitcal encoders with radial black & white patterns on paper glued to a disc. Or they drill holes in something. Not terribly high precision but they are doing it.

The key is really in the pulse width modulation and the feedback. The servo driver sends pulses of power of varying frequency or length to the motor. I don't know all the math. But it varies these pulses according to the encoder feedback. My oh so basic feel for this is that it kicks a pulse big enough to get the movement out of it and adjusts the pulse according to how much the motor is moving. The pulses can be positive and negative of course. Some motors will "sing" at idle as a result of these pulses going back and forth as the motor bounces between encoder lines. Called dithering. Sound neat but this can overheat a motor. Mine do not sing. There is dampening in the Geckos and I guess my encoders are pretty good.

That mill is interesting. Could be that the quill is in good enough shape on that machine that the back lash is OK for what he is doing. Wood is way more tolerant than metal. The grain is huge compared to what anything is in metal. Then alsmost everything gets sanded. Wood swells and shrinks a lot too of course.

I think that mill is a great example of right sizing your project. Mine is kinda over built I believe. But I do everything that way. Oh well. I note the abscence of a passage on ball screws to. So he's totally cool with some back lash. Either that or he's got something in his software to deal nicely with it.

Maybe he's got a nice smooth backlash comp movement. That could work too. Mach3 seems kinda jerky at that, but when you revese directions, it needs to compensate like now. So what to do about that? They would need a look ahead to determine when the direction change was coming and then slow down for it, do the backlash comp and then speed up again. Hmmm. Maybe I'll ask about it.

Home brew MAC based software! Cool! Now that guy is a real DIYer! I am very impressed.

-jd

Thanks for the info on servo motors. I found a couple of sites on the net that go into adding an optical encoder to a DC motor to make a servo. I found a 1/4 hp for $22 and I ordered a couple of encoders for $25 each. It looks pretty simple to add them to the end of the motor. 1/4 HP should be close to 1000 oz/in torque.

The guy who is regrinding my mill says he can get the backlash to .002 with a new acme nut. Before I sent it in, I had mine to about .005. Any tighter on the nut and it took too much to turn the handles. If you had .002, it seems that the software could take that up.

When I get everything back and installed, I will check the backlash on the spindle rack. Mine sure seems tight. Once I have the table back on I can put a load on it and see how much it wants to move. On your conversion, the ball screw it holding the quill in place? Have you done any test to see it if moves any under load?

Vince

I get some deflection on a rough pass ~.006 ish. On a finish pass it's fine. That's really about the same as the manual machine.

What I would like to do is map it with some kind of a pressure measurement, but that's a lot of equipment.

.002 can be taken up by the software. But, there will be places in the travel where it will be squirley. The ball screws are only going to help some. It's really a matter of the load being off center and causing the whole thing to twist some. At least that's what I think.

Make sure your lubrcation system is working good. It's worth a shot. You can always add the ball screws later.

-jd

I think I found some DC motors I can use for Servos, in fact the manufacturer made them with and without encoders. They are 60VDC. The spec sheet says 560 oz-in continuous torque and 3500 oz-in peak torque. They are 4" in diameter and 9" long. I powered them up and they all turned, but I think a couple of them need bearings. The unloaded rpm is 1600 and loaded 1400. Peak current is 70 amps and continuous duty amps are 8.5. I purchased 5 of them for $50 each. Most of the brushes are about half worn. I have some encoders on the way. Now I have to track down some HMR 7R10 bearings.

Vince

I talked to the guy doing the grinding on my table, saddle and knee. Once they are all ground they should be hand scraped to fit them to each other. He charges $90 an hour and quotes 4 to 6 hours to fit all three to each other, including fitting the gibs. He said I am welcome to come down and watch the process and even help it I am so inclined. He claims he can get better than .0005 in all directions.

Vince

510VA continuos. Sounds good to me. Have you loaded them to see what they really draw stalled? $50.00 ea. plus the price of some bearing and brushes, I'd say you got a deal. 60 VDC is perfect <IMHO> for the Gecko.

I gotta go look up some "motor math".

So now you need a lower voltage transformer. I'm not sure you said you actually got that 60V AC one or not. I think you just said you had access to it.

This should be SOP for everyone, but make sure you fuse the Geckos. If you crash and those thing start drawing full current you'll blow your Gecko. If all you blow is the power mosfet stage, it's repairable, I think, but still costs $$.

Shouldn't happen in theory since the encoder count will be 128 steps off in a heart beat. However, if there is an encoder loop failure then you will have a problem. A fuse could save a lot of money and damage.

Might want to bounce this off the Gecko support group too. I say fast blow fuses to protect the electronics. That would be the most conservative. This is not a heavy load start problem like an air compressor or a loaded conveyor. That's interesting... I guess in those hard slow start situations you would need to make sure the motor did not exceed the drives amps rating.

Post a picture of the motors if you get a chance.

Cool.

Thanks,
-jd

That still sounds like a deal to me right now. I gotta find someone around here to do that. I would sure like to have everything tighter than it is. It'll cost me $200 each way to have the machine moved. Well, I could rent a car carrier I spose. I'd want the ways on the pedestal done too.

Thanks very much for the info.

-jd

Since someone is going to have to take the mill apart to work on it, it might as well be you. I used and engine hoist to take mine apart. I would venture to guess that the heaviest part is the column, about 1,000 pounds. My engine hoist lifts between 1000 and 4000 pounds depending on how far out the arm is. If you know someone with a pick up truck you can fit it in the bed pretty easy and save yourself some money. If you don't have an engine hoist, use the money you would have spent to have the machine moved and buy one. I think I got mine from Costco. It breaks down into a fairly small package. I have used it to move in my mill, lathe, 600 pound wood burning stove, fountain etc. Once I got one, I found all kinds of uses for it. And yes, once I did use it to lift an engine.

When I get the parts of my mill back I will post some picture of the hoist in use.

I think I am going to start a new thread on my next post. I feel like I have hijacked this one.

Vince

I do have the engine hoist. I also have a chain hoist over the machine. So, yeah, that's absolutely a possibility.

Thanks for the posts.

-jd

hi


very nice job jdelaney44 and the other guys too

you guys amaze me with all the great work you do in here

now i have all the inspiration i need to get cracking and do my mill also to a CNC unit

mite have to tread lightly though as im new to electronics

god i love some of the work you guys do in this forum making me extremely jealous

cheers

FPV - Thanks very much!

-jd

I started a new thread on my conversion.

http://www.cnczone.com/forums/showthread.php?t=18178

Vince

JD, I gotta say I've read this thread a few times and it is one of the best if not the best all around convertion thread on CNCZone. Thank you for you time in sharing and the amount of details you always share, I learn stuff from all the tidbits constantly.

I'm starting a CNC convertion on a 1979 Webb Bridgeport clone that has seen better days but isn't all that bad (I don't think....). This thread, along with Vinces and several others has given me a ton of insite and saved god knows how much time.

Thank you very much folks,

Shawn

Thanks for the compliment. Please do up your own thread too if you have the time. Glad it has been of some help. Vince's thread is really good, yes. I am amazed at how fast he was able to get things done.

Best,
-jd

JD
Just wish you had done yours before I did my manual conversion rather than at the same time, could have saved my head hurting so much LOL
I wish I was able to write up a thread like you and Vince have done but I just dont have the writing skills (or maybe I am just too lazy ;) )
Hood

Well better late than never I suppose. This post has been successful beyond anything I imagined. It's up over 12000 views now. When I started my build I could not find a start to finish post out there. So, that's what I set out to do. For better or worse it seemed important for people to be able to see what they were getting into.

I'm going to be moving in about a year. I hope to get a place with a big shop. I feel the urge to do a Series II.

Hood, from your posts I think you write fine gets the point across. I don't see Hemmingway or Emerson hanging around here!

On a more technical note...

I started having some problems with losing steps. It's only with programs that have many, many short moves. When I drop the max speed or the acceleration, it's OK. So, I'm going to swap out the transformer to see if getting it that 15 volts I can squeeze in there will help. Doesn't sound like much, but that's like 25% of the 56V I am pushing now. Should improve my rapids a little too.

I am going to try one of those trannies from www.partsexpress.com

-jd

Hood, from your posts I think you write fine gets the point across. I don't see Hemmingway or Emerson hanging around here!
Ahhh well it must be I am too lazy then ;) To tell the truth I have great intentions of writing up as I progress but just get caught up in the build and I forget to take pics at every stage so there would be large chunks missing from a thread if I started one.

On a more technical note...

I started having some problems with losing steps. It's only with programs that have many, many short moves. When I drop the max speed or the acceleration, it's OK. So, I'm going to swap out the transformer to see if getting it that 15 volts I can squeeze in there will help. Doesn't sound like much, but that's like 25% of the 56V I am pushing now. Should improve my rapids a little too.

I am going to try one of those trannies from [url]www.partsexpress.co
Are you using backlash comp in Mach? if so I remember seeing some people having problems when also using constant velocity mode combined with backlash comp. Actually I think Vince had this problem recently, think it tends to show up when lots of short movements are called for. The solution is to turn off constant velocity and use exact stop or dont choose backlash comp and keep constant velocity, I decided on the latter.
Hood

Yup, Hood I remember just recently reading that as well about the backlash comp. I just got one of the "New" style Taig Closed loop Stepper CNC mills and while playing around with a router bit and a .5" peice of MDF it tweaked out and lost it. I am planning on checking that to see if I may have dunced up that setting while poking around. I have no darn endmills that fit this little thing yet so I haven't been going too nuts to look at it. Though I think this little mill is about to get a workout, keep reading to see what I mean;-).

JD, which Tranny are you referring too?

I'm about to start a new thread on my upcomming conversion, I've got the same decisions to make as every one else already has, or is about too...

Servo vs Stepper, AC or DC, Rockford ground ball screws/nuts or the others.

I'm really wanting to go all out with 2k-3kw AC Servos, and I probably will if I can find drivers for them that can handle the power. I have 3 phase power as well so in "theory" I should be able to find a deal here or there on industrial equipment others don't want to mess with due to the 3 phase headache.

I'm a little anti-stepper tonight;-), the Taigs little drives just seem so slow to me. Though if I can get some serious feeds and repeatable numbers I would still consider them on the BP conversion. I know its been talked to death, but feel free to chime in with opinions no matter which camp your in.

I think Skyko Pixie controls with either a homemade power supply or if I can find a decent deal on 3-5 industrial drivers I'd be golden. I'm still learning, ALOT, so feel free to tell me I'm crazy if need be;-).

long story but my "used" Clone BP mill (79 Webb 9x49) ended up having a "few" issues, broke quill feed, and the damn spindle motor smokes after a few minutes and gets WAY too hot, no Z Jack Screw handle, Y Axis binds in one direction. Sooo, I've been talking with the guy I purchased it (a 1979 Webb s2 BP Clone) and a 17" x 49" Cadillac Precision gearhead gap bed engine lathe with class 7 bearings from and he seems to be willing to make things right. As in probably trade some other stuff out to make up for a few honest headaches. I'll refrain from listing the eBay Sellers name until we resolve it, but I'm guessing he's going to make it right, which is cool.

The Lathe really seems nice, though it is missing the tool post and I'm waiting on an electrician to pull another panel of 3 phase off of our shops transformer before I can wire it up and play. At 4200lbs it is BIG. I was looking on eBay and I think that this LATHE (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7613475705&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1) is actually the exact same lathe but re-badged for a different manufacturer, albeit a fair bit newer I don't think that ones got the precision bearings this one has. Every single knob is identical and the casting looks to be identical too. I got a much better deal though;-).

Any thoughts on the XYZ (Actually Maybe putting the Z on the Knee) running with 3KW AC Brush-less Servos, 2048 Line Encoders. And more likely than not a Spindle motor swap to a decent Servo with direct speed control from Mach???

For example something like these Servo Motors (http://www.tigercnc.com/images/3kw_spec_800.jpg) was a thought, I'm still not up to the numbers on gearing and what not but for a Z Axis on the Knee with the knee + table weight + up to the rated 750lb workpiece size (probably 350 lbs would be it for me though) would it be better to gear down a 1KW that can spin at 3500RPM continuous at 50 in/lbs or a 3KW that can spin to 2000 RP M's at 150 in/lbs??? Guessing I would say bigger = better, until I try to find a Brush-less Driver...

Is it dumb to think of direct driving the Axis's? As for actual resolution and repeatability is it better or worse to direct drive vs gear down?

For those wondering, I have had money down on a Tormach but there seems to be a shipping discrepancy and it will or would have been arriving in June instead of mid-late April (Haven't decided if I have to back out due to the timing of things yet). Very nice folks, but I'm in need of a functional machine and this looks to be the path of least resistance/bang for the buck at the moment.

OK, I guess I officially need to stop hijacking JD's thread and start my own :cheers: . I'll try to rewrite this in better order in a new thread later today time permitting.

Shawn

I'm looking at the 50V 800kva toroidal tranny. I'm watching my power right now to see if I can push it to 55V. I think that's too close for the Geckos. 55 * 1.4 = 77, Geckos go boom at 81V. So I think 50 to get 75 out is as close as I should really go.

CV mode eh? I will have to check that. Good tip. With all these short moves CV would seem to be a moot point. There's not even room for the acceleration to finish.

I am using back lash comp and I apparently have it dialed in as well as it needs to be. The program has three sections, each with a different tool and it hit the mark every time. For whatever it's worth on the stepper debate, I am using servos but this is still open loop and with the speed changes it's perfect. BTW this program took about 12 hours to complete. This was over two days. I stopped it when I had to go out or sleep, shut down the machine, left the computer on, then fired it back up when I got back to it. Went away, did some other things around the house, while it ran, etc....

So this was a very successful run out of the machine last weekend. I just slowed the max feedrate to 10 ipm and cut back on the acceleration. The part is pretty complex now. several circles and spirals for artistic / design reasons. I'm trying to pretty up the product. So...pardon me if I don't post a picture just yet, it's still under wraps.

Sounds like everyone else is doing pretty well too. Great news.

Thanks,
-jd

800 KVA, sounds a little big. What would be larger than your entire mill ;-)

Vince

Yeah...... Maybe 800 K VA is a little big, eh? Meant 800 VA. Still haven't done anything on it. A bunch of stuff is on hold now. The day job dried up, looking for work again.

Best,
-jd

The new transformers are finally on order. This will get me up to 70V from 56V. That's a 25% increase.

The power supply circuit I last posted should be corrected with respect to the inrush limiting resistor. I have tested a 100ohm wire wound ceramic resistor and it works much better. The 200 ohm was too big with the Geckos hooked up and providing a draw. The 100 ohm yields a charge time of about 1 second. No upstream fuses blowing either. :cheers:

V=IR

220 = I * 100

2.2 = I

484 watts

Cool, the resistor is rated at 50W and it will take 10 times it's rating for five seconds. At least that's the Ohmite spec...

Yeah, that's better. I had it limited to 1.1 amps with the 200 ohm.

Regarding NTC thermistors. I'm building a supply for someone retrofitting a mill. This go 'round I'm going to go with the Negative Temperature Coeficient Thermistor for in rush. If you recall, these start out cool with a resistance and then the resistance goes down as they get hot. This eliminates all the active components in my power supply.

But what size do I get?

So at www.ametherm.com I get this formula:

J=1/2 C (V squared)

C = Farads

The V I am storing is going to be 70V with the new trans.

J = 1/2 * (56000uf/1000000) * 70 * 70
J = 137.2

I verified this at these sites -
http://www.electronics-tutorials.com/basics/energy-stored-capacitor.htm
http://www.electronics2000.co.uk/

So at Digikey I can get one rated at 300 Joules and 20 A continous current. They are five ohms. I know I need 11 ohms to get the current below my 20amp fuse.

220 = 20 * R
11 = R

So, I think I will use three of these in series. Each will throw some energy thus giving me some pad in terms of the energy passing each resistor.

220 = I * 15
14.6 = I

Allowing for some component induced error, that should get me below the 20 amp fuse / breaker.

OR I could get five of the ones rated for 30 Amp & 3 ohms. A little more $$$.

Need to think on it I guess.

Here's a catch.

These things look like they can run HOT. At full current they say they run at 200+ degress centigrade. 392 degrees F. Ouch! Now I'm probably never going to get up to 20 amps unless all three motors stall and then there will be fuses blowing downstream. But these guys will need to be protected from things touching them. We don't want any 'o them thar fires. Y'know? (flame2)

Well, that's the latest. Hope everyone else is doing well.

Best,
-jd

Did some more figurin'

The Avel Lindberg transformers I am using have a secondary current of 8 amps per leg on the secondary. 16 amps in parallel.

The formula for the transformer current is -

Ip = Is * winding ratio

winding ratio (WR) = Vs / Vp

WR = 50 / 115 = .435 (115 is from the spec sheet)

Ip = 16 * .435
Ip = 6.96 = +/- 7 amps for each trans.

I am using two so 14 amps. So at 20 amps we have 6 amps of safety or about 43%. A little much, but the next size down is 15 amps and that's too close.

Also recall that I wire the two transformers in series across the 220 hots. This still seems odd to me, but it works.

So it would appear that the 20 amp NTC Thermistor is the right choice. I'll go with three so I have 15 ohms thus limiting the in rush to less than 20 amps.

Best,
-jd

John: Really admired your mill conversion, just wondered how the mill is performing for you over the last couple of months ? Do you get to use it much ? And has it been as accurate and reliable as you envisioned ? Your build log sure helped me ( and a lot of others ) while I was doing a retro on my Tree Mill.
Thanks


Adobe ( old as dirt )

Thanks for the compliments!

I have not cut anything in a couple of months. Been tied up with getting a new day job and starting some .NET classes, helping out a couple folks with some CNC stuff and tiling my floor. Whew!

Accurate, yes. Reliable, not sure yet. Need more hours. With respect to the accuracy I probably had very reasonable expectations after months of on line research. I went over the machine with a dial indicator before I bought it so I knew what I was getting into. The electromechanics are scary accurate, well unless I run the IPM too high. The base iron is the real issue for this rig.

As always glad to hear the post is helping people.

School and work are settling down. I hope to start making chips in a few weeks. The floor can wait a little.....Don't tell my wife.;-) Kidding. She's been a terrific supporter of the project.

Best,
John

Well. Got the next power supply version built and load tested. The 5 ohm NTC Thermistors work great. They do get hot but not blazing hot.

This one is for a friend. Will retro fit mine soon.

My machine continues to work nicely. I have not used it a lot, but when I need to use it, it does it's thing.

More details on the new supply design in a while.

Update - uploaded one pic. More to follow. Lost my mini USB cable.

This is with a low power bench test using a 300W regular light bulb. The final test rig was seven 300W bulbs and one $20.00 heat gun. The heat gun worked nicely as it had a DC motor and a bridge rectifier built right on the back of the motor. So it didn't matter how I plugged it in to the DC side of the supply.

The bulbs drew about 2 amps each. The heat gun pulled 6 amps. All tolled it hit 20 amps. I rewired after the first 20 amp test. Went with bigger wire and more runs.

Things that get hot:

The bridge rectifier
The NTC Thermistors
The wires at the recitifier
The trannies start to warm up too

This was about 1300 - 1400 VA. The trannies are rated at 800VA each. If you wanted to run it at 20A continuous you would need really good cooling. This will require decent cooling for the 15A I fused it at. That last 5A makes a big difference.

The trannies are rated for 55 deg. C temp rise at full power. So they need cooling to get that under control.

The caps stayed cool really. I was expecting some heat off them at full power. The wires to the caps got a little warm.

My concept going in on these is to over build so we don't end up running hot. I think I've gotten there. We'll see once this gets installed and running.

Best,
-jd

Here are some testing / power supply Pics.

First is the full load test with the seven 300W bulbs and the heat gun which is out of view on the floor.

As I think I mentioned this is pulling 20A total. 72V max. At full load it dropped to 63 Volts.

2nd is the NTC Thermistors. BTW, these make interesting fuses. I blew up a couple in testing. Blew up is not an exageration either. $6.00 each. They are not much more expensive than a good fuse. Oh well. $12.00 education, priceless. ;-)

3rd. is the fuse block. Notice that I doubled up on the 12 GA wire. I can't get 10 ga or 8 ga in small amounts with high temp insulations locally. This is THHN building wire. Stranded. Courtsey of Home Depot of course.

4th is the top of the caps. I went with my triangle mount again. This is really stable. Note the bleeder resistor and the LED. I like the LED so I know the caps are still hot. The bleeder resistor was selected to be slightly higher than the Geckos this will eventually be hooked up to, at idle. That ensures the bleeder does not see current until the Geckos are totally off line.

Had an interesting learning experience.

So, if you charge up a cap and discharge it by putting a resistor across the terminals you'd think it was really discharged right? Checking it with the volt meter shows nothing. Discharged right? Not! Try hooking it up to another cap that has never been charged or has been sitting around for a while. I got a little spark and backed off quick!

Measured the potential between them and I got 8 volts. Not a big deal except that these are 20,000 uf caps. So there's a bit of juice in there.

So I put (+) to earth ground on all of them (across a resistor, 100 ohms I think.) to get them equalized before I hooked them up again. All is good. No sparks!

As always, be careful, this stuff can kill you. Seriously.

Best,
John

See attached.

Regarding the costs.

Don't forget shipping and tax..... Shipping on the transformers is a lot. They are heavy.

Also don't forget an allowance for hardware and some money for the mounting plate. This was built on a piece of surplus 6061 that's about 0.50 thick I think.

You also might want to allow for blowing up a few fuses and such.


Best,
John

PS -updated file on 2/25/07 with wiring diagram and a couple of corrections. I left the bleeder resistor off the schematic and did not have a spec listed for R3.

Did some more figurin'
The formula for the transformer current is -

Ip = Is * winding ratio

winding ratio (WR) = Vs / Vp

WR = 50 / 115 = .435 (115 is from the spec sheet)

Ip = 16 * .435
Ip = 6.96 = +/- 7 amps for each trans.

I am using two so 14 amps. So at 20 amps we have 6 amps of safety or about 43%. A little much, but the next size down is 15 amps and that's too close.



Correction to above: The max continuos rated current of the four windings in parallel would bE 32 Amps. 8 A per winding. This is off the Avel Lindberg spec sheet.

But as I noted, running at 20A got things plenty warm and I think you would need to pay extra special attention to cooling at 32 amps. I'm certainly no cooling engineer, but it seems obvious after the bench testing.

Best,
John

Quick update. Few weeks back I installed the new transformers on my power supply. I'm still experimenting with the acceleration settings in Mach 3 but it looks like I'm going to be able to get a stable max ipm of around 50 ipm.

So bringing the voltage up from ~56 to about ~72 made a difference.

Recall that my motors are 100V motors. So this confirms for me that making sure your motors are close to the max voltage of your drives and power supply is very important.

If I get some cash, I may switch out the motors for something around 70 - 80V.

I want to throw something out there too. The common concensus is that you only need linear or unregulated power supplies. I want to start making the case for regulated supplies. When I load tested my last power supply build, the voltage dropped significantly under full load. There's a lot going on there I know. And I have a ton to learn about power supplies still. But it seems as if regulation might not be such a bad idea. Just a theory at this point. Yes, it's a cost trade off too. Getting into a regulated supply opens a can of worms that might be just as well left shut.

There is also the very true point that the servo drive regulates the effective voltage, or maybe power is a better term, very well so further regulation is not required.

Best,
John

Quick update. Few weeks back I installed the new transformers on my power supply. I'm still experimenting with the acceleration settings in Mach 3 but it looks like I'm going to be able to get a stable max ipm of around 50 ipm.

So bringing the voltage up from ~56 to about ~72 made a difference.

Recall that my motors are 100V motors. So this confirms for me that making sure your motors are close to the max voltage of your drives and power supply is very important.

If I get some cash, I may switch out the motors for something around 70 - 80V.

I want to throw something out there too. The common concensus is that you only need linear or unregulated power supplies. I want to start making the case for regulated supplies. When I load tested my last power supply build, the voltage dropped significantly under full load. There's a lot going on there I know. And I have a ton to learn about power supplies still. But it seems as if regulation might not be such a bad idea. Just a theory at this point. Yes, it's a cost trade off too. Getting into a regulated supply opens a can of worms that might be just as well left shut.

There is also the very true point that the servo drive regulates the effective voltage, or maybe power is a better term, very well so further regulation is not required.

Best,
John

Hi John,

Voltage sag amounts to losing torque due to lost watts. So you are on the right track. Not all servo systems regulate the effective voltage. So a regulated power supply is a good upgrade.

Some time ago I posted alot of questions about using regulated supplies. It was obvious that most thought that they were a waste of time. Even a commercial unregulated version that I found claimed a 10v drop at full load. I can't remember if I posted it here or in the Mach3 forum.

I agree with you that regulated power supplies are very important to a well regulated and accurate system. One way to do this was to find a rack mount supply already working that just needed to be wired in. That was much cheaper and easier than trying to design and build regulated supplies. My system uses 5 amps continuous and 10 amps peak dc output per axis. There are 3 axis. So that makes the AC side pull up to about 15 amps peak from 120vac. The peaks don't happen very often. The worse that can happen in a regulated supply is that the voltage droops a bit at peak loads. If you can run a rack mounted regulated supply from 240vac, you won't have any voltage sag.

Good luck on your quest.

Mike

Mike, thanks for the reply. I was beginning to feel like I was on an island on this one...

Mike, thanks for the reply. I was beginning to feel like I was on an island on this one...

No prob. I proved that it works on my system, no matter what the nay sayers say.

Mike

Could I get a review on the write up from someone? I tested the circuit so I know it works. But I might have my terminology screwed up. See the attached post.

Best,
John

Strike this! I need to refigure the math!

John,

You don't really need the 1.5K resistor. The series resistor (shown as 10K), serves to limit the current. I haven't checked to see if 10K is appropriate for the optoisolator you are using, but it is probably about right.

On the subject of power supply regulation, I don't believe that it is necessary for this application. The voltage affects the servo speed; not the torque. That's controlled by the current. If you are worried about achieving a certain maximum speed at maximum load, just use a higher supply voltage. In practice, though, maximum speed will occur when traversing at no load.

I could imagine that poor regulation could affect the servo tuning, but in practice, tuning is not that precise, anyway. Other things like varying part mass, material, depth of cut and so on have a much more significant effect.

Ken

Ken

Ken, Thanks for the reply.

I put the 1.5k in there to form a voltage divider as you probably figured. That gives me a voltage of 1.56 according to the math. The LED is rated at 2V max. So you think the voltage drop across the 10K resistor will cut it?

Thanks,
John

Optos consist of an LED which has a specified forward voltage drop -- usually around a volt. They also have a specified current to actuate them. (Sometimes they specify a current transfer ratio. It might be 10:1 for a single transistor type, or 100:1 for a darlington type.)

So, if the diode drop is D (say .7 volts) and the desired current is I in milliamps (say 1 ma.), then for a 12 volt power supply, the resistance R (in K ohms) is:

R = (12 -D)/I
= 11.3/1 = 11.3 Kohms.

In that case, an 11K resistor should be just fine.

Ken

Took me long enough. I wanted to bread board this and test it. It works and by design seems to be right for the specific application on a Sound Logic Break Out Board.

Thanks for all the input and assistance.

Best,
John

Update on raising the power supply voltage. It's working pretty well with the actual program. I am not getting 50 ipm running the program however. But I was able to increse my "F" settings to 15 from 9. Will be increasing it over time. I hopeful I can get to hang at 20.

I got agressive on the first try an took it up to 30 ipm, no good. It did experience some step loss.

This program took about 10 hours to run. It's now down to between 6 - 8.

There are something like 25,000 lines that were generated by Visual Mill. I think I need to work with that some more too.

Still looking at the motor swap however.

Best,
John

So my wife named the machine Rosie. Presumable after Rosie the Riviter. Not the other Rosie. Anyway....

Attached is a short clip of Rosie doing a finish pass on a foam trial for what I hope will be a sand casting pattern eventually. This is part of three hours worth of video I am cutting down for an educational DVD for a younger cousin of mine. She wanted to stay and watch it all work, but had to go home to NY from CA. So I'm trying to get her the video.

While I was at it I thought I'd put something up here showing actual motion.

As you can see she is capable of rather nice rounds and curves.

The shop vac hose is mounted to a mag base not far out of the shot to suck up all the foam dust.

This program is around 25,000 lines. There are a ton of X,Y,Z moves all the time. I need to work on the CAM settings to dampen that. It's creating moves when it really doesn't need to.

Not bad for .002 or worse backlash, mis matched motors, and a kludge of other stuff that this thing is made of I guess.

So if you are thinking about doing one of these, the results are worth it. I think so anyway.

One of these days I'll post more video over at my own web site.

Sorry for the crappy video. Working on getting the file size up to the 500K limit.

Best,
John

So, after pricing out having my Bridgeport moved to a shop I recently rented and getting back prices from $500.00 - $2,000.00, decided to give it a go with rented equipment. I also had some time constraints with my travel schedule so getting this done on a Sunday was worth some extra $$.

Sorry no pictures of this yet and none of the actual move day. :-(

Anyway here's the gear:

5,000 lb capacity warehouse forklift
JLG "Triple L" hydraulic trailer (for the forklift)
Stake side F-Superduty Ford truck
A very understanding Wife
My best working partner ever, dear old Dad

All rented from United Rentals.

In retrospect the JLG trailer could have been replaced by normal tilt bed equipment trailer.

Plan A was to drive the lift and the machine onto the trailer and tow the whole shootin' match across town. The JLG trailer had a capacity of 10,000 lbs. The forklift weighed 9,200. The machine is close to 3,000 with the CNC gear on it. No go.

The JLG trailer's bed drops flat on the ground. No tilt and a small ramp on the end. Very nice rig.

Plan B was to use the forklift as a crane to hoist it on to the back of the truck. That's what we went with.

Note, I was way to chicken to try lifting the machine from under with the forklift. It seems too top heavy for this. Maybe with a bigger lift.

The first challenge was getting the Bridgeport out of the garage. There was some big show at Disneyland (really) and all the lifts in the area were is short supply. So the short ones I could drive into the garage were all rented out.

I was able to get my hands on some skates at Wright Industrial Hardware over in Costa Mesa. Actually my wife was good enough to go get them for me since I was out of town. I'll post pics of those later.

She also tried helping me use a pry bar to work the machine up on blocks to get the skates under it. We got it up, but stopped and let it back down. Not especially stable or safe. Getting it on the skates was looking to be a dicey proposition. This was a week or two earlier when I moved some other gear with the same trailer as kind of a test run.

So after thinking about this and looking at the Bridgeport I decided to try using a floor jack to lift up the machine. But how?

On the front, my Y axis drive goes straight down. The bottom of the drive housing is low enough to where I can get the floor jack under it and lift the machine. I was a little worried about putting 1500 lbs. of load on it.

So I ran the table out until the Kurt vice was over the Y drive housing, braced the drive housing with wood between the Kurt vice and the top of the drive.

On the back decided to make a strut from the utility mount on the back of the ram to within 5 - 6 inches of the floor. Enough room for the jack. I had some thing wall 2x2 square tube from another project and some square 1/2 plates from my scrap pile.

I drilled a 1/2 inch hole in one plate to align with the hole in the utility mount. Then a 1/2 bolt was welded into the hole. This bolt was used to secure the strut to the utility mount point.

Then the plates were welded onto the ends of the tube. Got lucky on the tube length and did not have to cut it. Good thing since the band saw went with the first load to the shop.

So once the strut was made up and bolted on it was a simple matter of jacking up the machine. We jacked it up on one end about 2 inches at a time, blocked it, and jacked the other side. Did that twice on each end.

Then we put the skates under it and lowered it onto the skates. It's still on the skates so I can probably get a picture of that.

We used a ratchet cargo strap around the machine and under the skates to help keep them in place. This worked real nice when we picked up the machine.

Once on the skates we rolled it out of the garage by using some 18 ga. sheet metal strips for runners. The skate wheels are sealed bearing units and they get stuck really easily. It required a good shove, but we got it out. Had to help it with the jack at the slab joint between the driveway and the garage slabs.

Once out of the garage we could get the lift up to it. We took several measurements to make sure we had enough mast height on the lift to get the Bridgeport up on the truck. Oh my wife calls it Rosie.

The forks were put together in the center of the fork carriage. Mast up, carefully drive the lift into Rosie as close as possible to reduce the moment arm of Rosie's 3000 pounds.

Then two nylon tow straps were wrapped around the ram and the table and then the forks. Most of the load ended up on the ram strap. The table strap acted to stabilize the machine.

Did a very slow pick. Drove it to the stake side. Lifted it up, set it down on blocks to keep it off the skates, backed up the lift about 20 inches, picked it again and drove it further to the center of the truck. Done, on the truck.

Strapped it down, loaded the lift back on the trailer, headed to the shop. Reversed the process to unload and returned the truck, trailer, and lift to United. Done and dusted.

At present Rosie is sitting on her skates waiting to be placed in her final home.

Cost ~ $600.00 all tolled including the skates, straps and fuel. I could have had it done for that, but now I have the means to move her around the shop. I also have the confidence to move her again if need be. Next time it'll be faster and a little cheaper with the tilt trailer.

I can see where a beater used forklift can pay for itself quick.

Later,
John