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The Wizard
10-02-2004, 10:14 PM
Hi folks, I guess my building project has finally started after many weeks/months of planning, reviewing, playing with software etc :banana: .

My motors and controller came in on Thursday so I spent yesterday and today gutting an old 386 computer for the power supply and case and carrying out motor tests (I just couldn't resist spinning those motors ;)).

I searched high and low for a large heatsink I know I have here somewhere but of course with moving house twice in two years it's not to be found! In the end I decided to pull a pair of heatsinks off the 386 motherboard and used those to mount the power resistors on. I even mounted a 12V fan to help keep them cool.

The motors fired up at the first attempt and ran nicely (one is not quite as smooth running as the other two so I will use that one on the Z axis). I ran several batches of code through them using a number of different pieces of control software and the motors stayed cool throughout and the resistors were warm but not hot (you could easily leave your hand on them).

I have attached a photo of the test set up (ignore the rat's nest.....lol......it will be neater when complete. The controller is a Stepperworld SP-3HT and the motors are Superior Electric 75 oz./in. units.

Now I have to start on the woodworking side and get the machine built!

Larry Green

cncadmin
10-03-2004, 01:22 AM
Nice great start please keep us up to date on your progress.

The Wizard
10-10-2004, 11:29 PM
I still haven't been able to access my buddies wood shop but I have now priced the MDF for this project ($46 CDN incl. taxes) and in the mean time I have been busy making some parts that I can work on here. The first project was a set of three self-adjusting AB nuts. I decided to go with this design rather than a split type with adjustment screw as I had some round nylon bar available plus it gave me a chance to play with another toy of mine.

I have a Unimat SL/DB200 table top lathe/mill (early 70's vintage) and I was just about on it's limits in terms of size with these parts. 1.5" is about the maximum diameter you can hold in the chuck (with the jaws reversed) and the stock nylon bar was 1.5" diameter. Unfortunately the torque at that diameter meant I could only take 10 thou cuts otherwise the belts would slip so it took a long time and lots of winding those tiny handles to turn these parts but it was interesting and gave me a sense of achievement when it was done.

The slots were cut with the Unimat in mill mode using a .120" burr from my Dremel. I could only take small cuts again as I didn't want to break the only suitable cutter I had plus it tended to flex on the male part if the cut was too large.

The springs I found in the local hardware store and have a free length of 1.5" and compress to .5". They are 5/8" diameter and use .040" diameter wire. They load up nicely and have enough tension to do the job.

I made a tap out of a piece of 'all tread'. I turned a taper on one end and cut the slits with a cutting wheel in my Dremel. I also centre drilled the end so that I could support it on the lathe. With a centre in the end the tap started into the hole square and true. It worked quite well considering what it was but I may have to run it through the nylon a few more times (or open up the hole one drill size) as it is a bit 'tight' on the 'all thread' and I can see the motors having to work hard just to turn the leadscrew in the nuts.

I have attached a few photos for your viewing pleasure ;) . More info to follow as the project progresses. It will be next weekend before I can start on the wood so I think some handles/knobs for the motor shafts are going to be next.

Larry

Mr.Chips
10-11-2004, 11:24 AM
Larry,

Thats a good looking AB nut. Any new photos available?

Hager

The Wizard
10-11-2004, 11:48 AM
Larry,

Thats a good looking AB nut. Any new photos available?

Hager

Thanks Hager. Those are the latest photos :) I uploaded them as soon as I had the parts finished.

I will post more as I get parts made.

Larry.

The Wizard
10-13-2004, 04:28 PM
I decided to make the handles for the motors yesterday/today. These will allow me to turn the leadscrews by hand for set-up purposes or to back off the axis from a limit switch.

The grey parts are PVC and the black parts are polyethylene (material I happened to have available). The shoulder bolts allow the 'knobs' to spin freely while still being held securely. I also had to make two more taps (10-24 and 10-32) out of machine screws. Gotta love home made taps in plastic :) .

I have also cut the aluminum linear bearing carriers to length so this evening may be spent drilling holes for the mounting bolts. I am just hoping my tiny Unimat is up to the task....lol.

Larry

High Seas
10-13-2004, 06:43 PM
Wayyyy Cool.

The Wizard
10-13-2004, 11:03 PM
Wayyyy Cool.

Cheers High Seas! :cheers:

The Wizard
10-25-2004, 12:03 AM
Well it's been a busy week or so here and I have been pushing my tiny Unimat to the limits (and beyond) again!

I got the aluminum linear bearing supports made but unfortunately the Unimat wasn't up to the task of cutting the slots using a burr from my Dremel (no metal cutting end mills available) so I had to resort to the old skills and cut them out by hand using a hacksaw and a flat file. I have a medical disability that leaves me extremely tired after only a small amount of effort and all that hand working meant that I had to cut one pair of flats and then go and rest for a couple of hours to recover! Nevertheless I got them done and I just need to get the hardware to mount the skate bearings.

Next up was the adjustable blocks for the rails/pipes. This again turned out to be a big task as my material was slightly wider than required which meant I had to machine them all round using a 1/2" wood router in the Unimat. Once I had them square and to size it was on to the holes (all 108 of them!)

The mounting holes were nice and easy as I set up a jig on the Unimat so that I could just slide the corner into position and drill. The only downside was the whopping 3/4" of travel on the Unimat Z axis. The material was 3/4" thick and by the time you add in the point length on the drill and a bit of clearance above the part it meant that I had to flip the parts over to get a hole that went all the way through. Thankfully my jig was spot on and the holes lined up perfectly.

The large central hole was next which meant tearing down the Unimat mill/drill set-up and reconfiguring it as a lathe. All I had to make the holes were wood cutting spade bits so that was what I used.

The first problem I encountered was the fact that I could not 'swing' the larger of the blocks in the 4-jaw chuck as the corners of the block fouled on the bed. After some head scratching and pondering I wondered just how much I would have to remove from the corners to get it to 'swing'. Out came the Exacto knife and I started to pare small amounts off one corner until it cleared the bed. As it turned out I only needed to remove 1/8" at 45° so the corners of the four larger blocks got a quick trim and away we went!

The next problem to raise it's head was the fact that the Unimat just didn't have the power to cope with a 1-1/4" spade bit straight into the nylon. This meant that I had to work my way up in size but it also meant that after the first hole was drilled there would be nothing to guide the spade bit. I also placed a variable speed controller in the line so that I could slow the Unimat down as the slowest available belt speed was way too high for the spade bits. As it turned out the spade bits ran nice and true and didn't really need the point to centre themselves in a rigid lathe set-up. The finish was very good, almost glass like, and I was impressed with the way they cut nylon. It took a while to machine all the holes with having to go up in steps of every other size but I got there in the end. It helped that the smaller blocks only needed a 1" hole too.

Once the large holes were done I had to reconfigure the Unimat to mill/drill mode again so that I could drill and tap the adjustment screw holes. After the large holes this was a breeze and only took half a day to drill and tap all 48 holes.

I have attached a few photos and have more of the various set-ups if anyone is interested in seeing what I had to do to make these parts.

If things go according to plan I should be starting on the woodwork next weekend as my buddies woodshop is finally free (he has had an active project going on and wanted that out of the way first). More updates as they are available! :)

Larry

The Wizard
01-17-2005, 11:15 PM
Hi folks,

Sorry it's been so long since my last update but shortly after my last post I ran into health problems, financial problems and car problems (all in the same week!) These set the CNC project back quite a bit and then I had some 'must do' projects that had to be finished before Christmas. At least I did manage to get over to my buddies place to get the MDF boards ripped to size.

Since the New Year I have been going at the CNC project full tilt again and I am starting to make real progress (albeit slow). I am hampered somewhat by a lack of decent machinery and I am pushing my tiny Unimat DB200 to the edge and beyond with this project. I am having to make 9-10 cuts for grooves that could be cut in one pass with a decent router table (with micro adjustable fence) and the right size cutter.

I finished the last of the 'critical' grooves this evening and started drilling holes for the numerous bolts. With a bit of luck the majority of the Z and Y axis components should be ready to assemble tomorrow.

Over the holiday period the connector parts arrived for my wiring and I have already made up the 'unbilical' cables that will run between the control box and the machine and made mounting plates for the 'uni-lock' connectors. Now I just have to find a suitable switch to use as an E-stop and a 12V DPDT relay and the wiring side will be sorted as far as parts are concerned.

I will post more photos as the job progresses (there hasn't been that much to photograph recently...lol).

Larry

MIKE JEFFERS
03-19-2005, 05:35 PM
like the spinney spinney photo (drill swarf etc)
living i canadia as you do its probably 12 feet of snow outside best get on then
like the uni mat
regards
mike

The Wizard
03-20-2005, 12:24 AM
like the spinney spinney photo (drill swarf etc)
living i canadia as you do its probably 12 feet of snow outside best get on then
like the uni mat
regards
mike

Thanks Mike.

Although I am in Canada I am an ex-pat and have been here 12 years now. Thankfully we haven't seen 12 feet of snow this year but we have had snow on the ground almost continuously since just before Christmas and it is finally disappearing now.

As far as the machine is concerned........I have been busy as a beaver over the winter cutting and painting the wood parts and assembling the major components. Tonight we finally got the rails and gantry mounted on the bed and roughly lined up and tomorrow we will fine tune it and start on the Y axis.

I haven't posted any more photos recently as I felt everyone on here had seen enough photos of wood parts and drying paint but I will post more after we get the main assemblies mounted tomorrow.

Watch this space ;)

Larry

santiniuk
03-20-2005, 06:08 AM
Fantastic log so far Wizard. Please keep them pic's coming.

I'm envious of your machining skills :)

Hope your health problems are behind you.

Cheers.

The Wizard
03-21-2005, 01:41 PM
Fantastic log so far Wizard. Please keep them pic's coming.

I'm envious of your machining skills :)

Hope your health problems are behind you.

Cheers.

Thanks, Santiniuk. There is no need to be envious of my skills ( :) ) I am just trying to do my best with what little equipment I have available. I served my apprenticeship as a toolmaker back in the UK in the early to mid 70's and got my CGLI T6 in 79. Years later while working in the Engineering Dept. of a local College I got my CGLI CNC operator and CNC programmer certificates (they were new courses for the College and they needed 'bums on seats' ;) and all programs were hand coded and saved on punched paper tape!) I don't even have a workshop I can work in and all my machining (apart from cutting up the MDF sheets) has been done on the kitchen table!

As far as the health issues are concerned I am afraid I was hit with a life altering condition (Myalgic Encephalomyelitis or ME for short) that has no treatment and no cure and although most people do recover up to 60-80% of their former health it can take up to ten years to get there and they are prone to relapses if they push the limits.

We managed to get the gantry rails trammed up on Sunday and the gantry slides from one end to the other with just a small one fingered push (whoo hoo!) but the Y axis is another story altogether :frown: .

We spent at least four hours last night trying to tram up the axis and eventually gave up in frustration. I am suspecting that I have a slight bend in one of the pipes as I can get it trammed perfectly at one end but when the carriage is moved to the opposite end the bearings closest to the gantry 'wall' are good but the 'inner' end of the carriage 'slops' about quite a lot. If we set the rails so they are good in the middle then they bind at each end. I will take it all down later today and check the pipes for straightness to see if that is the problem (it's the only thing I can think of at the moment that would cause those symptoms).

I have attached a coupe of shots of the bed (or rather the lower section as there is an upper bed and a 'table' that goes on top of that) and the gantry. My wife even tried to shoot a short video (using our digital stills camera) showing how well it slides but unfortunately the lighting was too low and by the time I had brightened it up in my video editing software the quality is not too good (very 'grainy' and 'washed out') so I have not posted it here.

I will let you all know how I get on with the Y axis once I get it working.

Larry

The Wizard
03-26-2005, 12:12 AM
After three days of frustration I finally got the Y axis problem sorted out! It turned out that the upper length of gas pipe did have a slight bend in it roughly 6" from one end. When I held the pipe against the window (the best flat surface I could find) I could slip a piece of .004" paper under the end of the pipe and about 6" down it. That small amount of bend had been preventing me tramming up the Y axis! I tried straightening it but had no luck so I finally went back down to the local hardware store and bought a new length. This time I was able to tram up the Y axis with only minor problems.

After getting the rails on all three axes parallel and the carriages sliding smoothly it was time to set things up square. I taped a piece of paper to the bed and fastened a pencil to the Z axis then ran a line on the X axis followed by a line on the Y axis. Initial checks with a set square showed a very slight error so out came the protractor which showed an angle of 91° in the corner. I adjusted the Y axis rails by 1.5 'flats' on the adjuster bolts on one end and ran a second line. This time it came out at 90° using both the set square and the protractor but I will check it again once I have the machine powered up and I can actually cut a corner with it. The Z axis was set up using a large builders square that had been checked against an engineers square. It was slightly out (a .004" piece of paper 'just' went between the square and the top edge of the router mounting plate) and a quick 'tweak' of the adjusters soon put that right.

Next up was removing the now set up top pipe on the Y axis so that I could sand and paint it. It should be easy to get back to the exact spot it came from as I only undid two bolts on each end so the other two should act as a reference point. While the paint was drying it was time to move onto the leadscrews.

The Z axis was first and the only 'tricky' part was getting the two halves of the A-B nut and the spring together as it is located in a deep 'pocket' between the linear bearing mounts and the router mounting plate. I decided to leave the Y axis leadscrew until tomorrow to give the paint time to set up on the upper pipe. The X axis caused me a couple of problems as I discovered my 3 feet of 'all thread' was 3" too short after I had decided to mount my motors on brackets so that I could have bearing supports at each end. A quick trip to the hardware store didn't help as they only stock 3 foot lengths.......DOH! So I decided to buy a coupler nut and a couple of locknuts and extend the 'all thread'. It means I lost roughly 1" of travel on the X axis but I have lots of travel there so I am not too worried about that. Everything went together well and I now have to tackle the Y axis leadscrew tomorrow.

Out of curiosity I decided to attach my power drill to the end of the X axis leadscrew to make sure it ran back and forth without any problems. It ran nice and smooth with the drill spinning at quite a high rate but I was very surprised when I felt the leadscrew. It was almost too hot to touch! I am hoping it was due to the A-B nut being a touch on the tight side as the threads were cut using a home made 'all thread' tap. I doubt the stepper will drive the leadscrew at quite the same rate as my experiment which should reduce the heat build up somewhat but I will try to keep my eye on that in case it turns out to be something more sinister!

I have posted a few pics of the progress so far. It is beginning to look more like a machine and not a pile of wood and metal now. The last electrical parts I need are on order from Digi-Key and it will soon be time to tackle the wiring side. We're getting there!!!!!!!! :banana: .

Larry

ger21
03-26-2005, 07:24 AM
Use a little oil on your leadscrews, or maybe one of the spray on dry lubricants.

The Wizard
03-26-2005, 11:27 AM
Use a little oil on your leadscrews, or maybe one of the spray on dry lubricants.

Thanks for the tip Gerry. I have some spray on silicone lubricant so I may give that a try. It is intended for plastic parts so should be safe to use with the nylon A-B nuts.

Some nylons/plastics can react badly to regular oils and become soft and sticky. I have seen nylon lined motorcycle cables that looked like they were filled with chewing gum after the owner decided to 'oil' the cables!

Larry

The Wizard
03-28-2005, 12:53 AM
I got the pipe back on the Y axis after the paint had cured overnight and the Y axis leadscrew is now installed. Everything works fine and I sprayed the leadscrews with the silicone spray and they run much cooler now.

I started on the machine wiring this afternoon and have the cables to the motors cut to length (plus lots for adjustments ;) ) and the Amp-Tyco connectors soldered to one end.

I still have a couple of MDF parts to finish and I am still waiting for the last electrical parts to arrive before I can start making dust but each day brings the end a little closer!

Larry

Ray Hill
10-23-2006, 12:30 AM
Larry,
I'm a new member, thanks for your build sequence photos. Could you give me more information on the self-adjusting A-B nuts, size/dimension?
Ray Hill

Rance
10-26-2006, 07:46 AM
Larry,

So what's your progress been like? Are you finished yet? I'm interested to see how your motors are holding up. I plan on using small motors too for my first machine. Time for an update. :)

The Wizard
10-27-2006, 10:52 PM
Larry,
I'm a new member, thanks for your build sequence photos. Could you give me more information on the self-adjusting A-B nuts, size/dimension?
Ray Hill

Hi Ray, sorry for the delay in getting back to you but I only just got the notification that a new post had been added to this thread. I lost internet access 3.5 weeks ago after a very close lightning strike came into my house via the phone lines. It fried 3 out of 4 phones, my high-speed internet modem and the ethernet cards in the two desktop computers connected to it! :eek: All were turned off at the time too! :mad: It has taken my ISP this long to get a new modem out to me after the first one was apparently lost in the post somewhere and I only discovered the ethernet cards were fried today when the modem arrived and I still couldn't access the net (chair) . Thankfully I am now up and running again :wee: .

To answer your question. I made the A-B nuts out of some scrap 1.5" diameter material I had to hand and I believe it was nylon but I can't be sure which type as it was given to me as 'bar ends' with no means of identification.

Since working on the CNC machine I have had a major hard drive crash requiring a reformat and built a completely new computer (with another reformat) and when I went to find the CAD drawing of the part it was no longer on my hard drive (of course)! After some hunting around in my back-up discs I found the one with all the CNC drawings on it so I am able to provide that if you would like it but I would need to know if you can open CAD files in either DWG or DXF format or if I need to convert it to a JPG or a GIF file.

Larry

The Wizard
10-27-2006, 11:30 PM
Larry,

So what's your progress been like? Are you finished yet? I'm interested to see how your motors are holding up. I plan on using small motors too for my first machine. Time for an update. :)

Yeah, I guess I have been so busy doing other things I never did get around to finishing this build thread ..... sorry :( .

I did finish the machine, sort of, and made some major changes and then got into other things due to circumstances and never got back to it to finish it off completely (although just recently I have been saying I MUST get back onto this project again!)

I got it working with the controller and motors shown earlier in this thread but found that I was struggling for speed partly due to the 20 TPI leadscrews and partly due to the motors/controller I was using. As changing the leadscrews for larger ones (with less TPI) was not really on I changed the controller and motors and went with 200 oz motors, a much faster controller and a much bigger power supply instead of the computer power supply I was using. I also changed the control software from TCNC to Mach 2. After I made the changes the machine was MUCH faster and peformed more like I expected it to.

Unfortunately, when I tried machining MDF I found the dust created was a major problem (even with a shop-vac sucking the dust away from beside the cutter) as the machine was sitting in my living room at the time! I had nowhere else to put it at that time and I shelved the project until we moved (a house move was on the cards) and I have not really worked on it since. The house move fell through and we still haven't found a place and the machine is still sitting in the living room! (It's a good job I have an understanding wife ;) ).

I had planned on primarily using the machine to engrave perspex so I am hoping if I get back into it that the cuttings from perspex won't fly around the room like MDF dust does. I was only machining MDF to make a jig to hold the perspex sheets anyway and I may be able to finish that off either outside on my small router table (if the weather holds) or in a friends woodworking shop provided that I can get it set up dead square in order to finish the jig off.

Larry

Ray Hill
09-05-2007, 12:59 AM
To answer your question. I made the A-B nuts out of some scrap 1.5" diameter material I had to hand and I believe it was nylon but I can't be sure which type as it was given to me as 'bar ends' with no means of identification.


Larry,
Could you convert your file to Jpeg?

Thanks,
Ray Hill

The Wizard
09-05-2007, 01:53 AM
Larry,
Could you convert your file to Jpeg?

Thanks,
Ray Hill
Errrr....which file were you referring to? The plan for the A-B nut?

If so I will have to

A) Dig out my back-up disc as I have changed computers once and hard drives twice since I worked on this project...

and.....

B) Re-install my CAD software to access the file once found as I haven't re-installed it since my last HD format!

Ray Hill
09-05-2007, 04:16 AM
Errrr....which file were you referring to? The plan for the A-B nut?

If so I will have to

A) Dig out my back-up disc as I have changed computers once and hard drives twice since I worked on this project...

and.....

B) Re-install my CAD software to access the file once found as I haven't re-installed it since my last HD format!

Larry
Never mind!