J-Head CNC conversion Journal - TONS-O-PICS!!

[mxtras]

I'm kinda new here, so I hope I posted the PICS properly.

This is my rebuilt J-head. The out shots were all coming out really blurry, so I had my eyes checked, but they are still blurry....sorry - only one is attached. I am glad the background is not clear - who knows what kind of embarrassing garbage one of you would find in the mess! You'll spot a fuzzy image of my HF 9X20 lathe behind the mill....it's next for CNC. Bridgeport first.

I do not have digital photos of this machine when I first got it, but it did not look the way it does now. But that's a long story and I am getting tired.

There are a few photos of my homegrown one shot lube system - very adjustable, huh? Still tweaking the adjustments, but it lubes all the screws (Z included), the ways (of course) and the head. I broke it into two circuits so I could feed the heck out of the ways if I wanted to purge them after a nasty day of cast iron milling. This machine had grease fittings and many of the cross drilled holes were packed with some hard, foriegn material that did not resemble grease. The lube lines to the head are not run yet. I need to get inline check valves - to be continued. As you can see, I used nylon tubing for the lube lines. I am very satisfied with it's performance and appearance so far. Estimated cost - about $70 with some dumpster-diving involved.

And finally - the beginnings of the brackets for the steppers.

I spent most of this afternoon sketching out the brackets. I started out on a sheet of paper then graduated in to ACAD after I had a clear image in my head of what I wanted to do. Then, of course, after I got everything into ACAD solids, I pretty much threw the paper design out and started compacting and refining the drive system and bracketry. I want it rigid, protected and tucked out of the way.

One thing I could use input on - I was NOT originally going to put the gear directly on the shaft of the motor - I was going to use a coupling and a seperate shaft supported on two or three roller bearings, but now I am thinking I am going to mount it direct and support the outboard end of the motor shaft - opinions?

Anyway - I will use this thread to post progress in the coming weeks (months).

Scott

[jdelaney44]

Scott, SWEET lookin' machine. Nice job.

On the out board bearing, most of the drives I have seen (home brew and commercial) go right on the motor with no additional support. Seems to work fine. I would resist the temptation ot over build. I've done that on my quill drive. It's way too big. Stiff, but over kill in the wrong places.

Also, I am building my quill drive first. I learned from somone else that the "right" way to to it is to get the X-Y going first and then use that to do the much more complex quill drive. I did it the other way 'cause if I don't get the hard stuf out of the way first, I tend to burn out and never get things done.

Keep going, can't wait to see the end product! Looks great so far.

Oh, what did you pay for the scraping?

- jd

[mxtras]

Thanks, jdelaney44

Overbuild? Who me?? ....Yup. I have a reputation for going over the edge...and down the cliff...and into the creek.

The control is complete - motors spin, G-code talking, ins and outs going in and out...

As far as the quill drive, I was seriously considering driving the knee instead and leaving the head alone. The drawback to driving the knee would likely be speed as I am going to have a high reduction to get the torque - but I think it's the way I am going to go unless someone gives a compelling reason as to why it is NOT a good idea.

X and Y first - I'll agree with that! - thanks for the suggestion! I do usually pick the hardest tasks first also - then the rest is downhill, right? ..right along with my enthusiasm....

As far as the ways - I did NOT rescrape! I did minor work to 'soften' some scoring in the saddle but for the most part, the ways blued out exceptionally well. This was a one owner machine (bought and picked up directly at the Bridgeport factory in Connecticut) that I paid only $1200 for from a widow that was selling off her husband's home shop. I looked for about 8 months before I found this one and although it was hard at times, I kept my patience and money long enough to find this machine. It was in very good, if not excellent, mechanical condition. and I was left with half the money I expected to spend.

The feed mechanism internals were destroyed, but the machine mainly just needed a little fluffing up and TLC. It has the original X and Y screws with .004" backlash in X, .002" in Y. I am going to leave the screws in for now.

With pickup costs and parts, I am about $2100 into the machine itself (not the controls).

Thanks for the reply! I wish I had digital pics of the machine condition when I got it. I have a ton of 35MMs - many rolls are not even developed yet as this project has moved pretty fast so far.

More to follow. I will try to post at least every other night. Thanks!

Scott

[Mcgyver]

Originally Posted by mxtras This machine had grease fittings

Hi Scott,

looks like you are going to end up with a very nice machine

btw, those are not grease fittings, or at least are not intended for grease. the zerc fittings are also used for oil, although it can be chore to find a pressure oil gun.

Can we hear more about how you put together the one shot lube system? I don't know that much about them, but remember being told it was the valving that was the tricky/expensive bit on commercial ones. How is this done? Some sort of equalized pressure valve where the line goes into the casing? Otherwise how do you balance the system? It looks like you've a bank of valves on a manifold, is this where you are going to control balance?

[mxtras]

Mcgyver -

Based on the condition of the rest of the machine, I can't imagine the previous owner not reading the maintenance instructions but it sure looked like he was using grease for the ways! I still don’t know what to really use – Vactra #2? I know I am not using grease.

I looked and looked for information for a home-brewed lube system on the internet with no luck. I got some helpful info, but I could not figure out why nobody had made mention of putting together an adjustable point central lube system.

I am using an 8cc/shot hand pump ($18 off Ebay) that's fed into distribution manifolds and then to each circuit with ¼” nylon tubing and Legris push lock fittings. The braided lines are SS braided, nylon lined faucet hoses and they will hold 100 PSI. The nylon will resist the oil reasonably well unless aggressive synthetics are used.

At each circuit, I put an 1/8”NPT adjustable needle valve to regulate the volume of oil each point gets - to balance the flow, yes. I started by closing all needle valves then I opened the valves to all the ways one turn each as a starting point and made sure all were flowing. With the tubes clean and empty, it was easy to see the 'speed' of the flow, so I made visual adjustments to approximate the same volume to each point (based on the speed of the oil through the tubing) while making sure I maintained at least 25 PSI output pressure. Then I cracked the remaining valves and made adjustments based on the flow - guess work, basically. I do not have a flow curve for the valves and did not look at things that closely – I suppose it would be easy enough to do using the gage and with that information, you could absolutely duplicate a commercial system. I will be more analytical if a failure becomes evident but right now when I pull the handle I see oil coming out from each location as desired – including the table nut. The difference is that with mine if you get a plugged passage you can isolate it and try to blow it clear using the pump, or I can isolate the saddle to help recover from a dirty cutting job.

I added a drip wick on the bevel gear set for the knee screw and added a crap guard to shield the gears from chips. I also drilled and threaded the Z nut for a lube line.

I looked into the commercially available systems. They were comparatively expensive, non-adjustable and not available at the local hardware store. I was too lazy to do all the investigation and calculations and I just wasn’t comfortable going that route, so I built the system you see with infinitely adjustability and expandability.

I had also read about fixed systems that would get plugged up from infrequent use – I think it was when Vactra was used, if I am not mistaken? That info is somewhere on the net – can’t locate it again but I will find it if you guys are interested. I read that if Vactra is left to sit in the lines without activity for extended periods it tends to coagulate or clot and can foul up the small springs in the flowpath of the fixed systems with the only solution being a complete system tear-down….not my idea of a good system.

Sorry to ramble – but you asked for details!!

Scott

[Mcgyver]

the details are much appreciated. Adding that system will promote good habits and I like the kiss approach - I think I'lll do the same. I use 20 or 30 wt (can't off hand remember) way oil. Not using grease seems to be one of those unwritten things everybody knows - except for newbie Mcgyver many years ago when he got his mill. The only way to really get rid of the the grease is to disamble and clean everything including the lines.

[bill south]

Scott;
What are you going to drive the axis with. Servo's or Steppers and have you sized them yet. I also am interested in a home shop BP mill and will go through the same conversion you seem to be performing. Please keep us posted!
Bill from Spartanburg

[Willyb]

Hi Scott

Really like your lubrication system on your Milling machine. What and where did you get the plastic line and fittings for your system? Also what are the brass control valves from? Thanks for the help.

Regards
Bill

[mxtras]

I don't know what's more fun - doing the project or sharing what I learned with everybody else! It takes time, but this is a kick!

For the lube system:

I used Legris 3109 series pneumatic fittings - check out www.legris.com. I scrounge leftovers after a project is done from my employer so I have almost unlimited supply. ….same with the tubing. there are many manufacturers of this type of fitting and it is the easiest thing to use in my opinion. Just make sure you cut the tubing straight and clean - use a new knife blade and push straight down to cut the tubing to length.

Upon closer inspection, it looks like some of the ¼” (6MM) plastic tubing is polyurethane and some is nylon. 1/4" and 6MM use the same fittings from Legris. Check the chemical resistance of the material against your lube to ensure compatibility (go to http://www.coleparmer.com/techinfo/ChemComp.asp for a relatively comprehesive, easy to use, searchable database of compatibility).

Legris Distributors in Ontario:

INNOVATIVE CONTROL SOLUTIONS
ON Tel: (905) 709-4220
@: sales@icssci.com

TYMATIC CONTROLS
ON Tel: (905) 336-3690
@: paultymatic@bellnet.ca

ROBERT CROTHERS ASSOCIATES LTD
ON Tel: (416) 292-7901
@: rjowett@robertcrothers.com

DOMINION FITTINGS
296 CARLINGVIEW DRIVE
M9W 5G1
REXOALE
ON (no phone listed, sorry)

The brass valves were purchased from a local hardware store. There is no manufacturer on the package – they might be made by Weatherhead – don’t know for sure. I cut the handles so they could be packed closer to eachother on the manifolds. The manifolds were made from a chunk of aluminum, cut on a 12” miter box saw (DeWalt) with a 80 tooth carbide blade (Diablo) and the holes were drilled on a P.O.S. drill press, tapped by hand using a center in the drill press to get started straight. All threads are 1/8"NPT.

I will post lots of detailed photos (in this thread – I guess that’s ok ? ? ) for all that may be interested in the lube system, so check back.

Scott

[mxtras]

For each of the 13 points on my manifolds, I used a hex nipple, a $3 needle valve and a Legris fitting. Now I recognize that I need to add a check valve at each point.

SO - I have picked out a Legris, quick connect, flow control needle valve that has a built in check valve - Part #7065 56 11 (1/8"NPT, 1/4" tube). I hate re-work. I should have known flow-back would be an issue, but at the time, I did not consider it.

This single fitting seems like a MUCH better option. It will also be more compact. I will complete the lube system and post updated photos in a few weeks.

Should I keep this thread going - post updates and photos here? Thanks.

Scott

[mxtras]

The first two pics are the majority of the system. The empty space with that shelf looking thing is space for the stepper to traverse with the saddle. I am mounting the motor backwards so that it does not hang out past the end of the table - the motor is in it's approximate home in the second pic. In either pic you can see the basic layout of the lube system. The head is not plumbed in yet. I will give a more detailed description if you ask....for now - get the popcorn, get comfortable and look at the pics.

The third pic is a close up of the manifold under the lefty's side of the table, mounted to the saddle. Notice how the lube has drained down inside the tubing - hence the need for check valves at each point. (previous rant). I loose about 1/4" of table travel with this configuration but I can't recall ever cranking the table on a Bridgeport to the stops anyway. I actually considered cross-drilling the saddle for the lube passages but I feared weakening so I chose the more logical route of running the tubes through the saddle to get to the other side.

What you can't see is how I connected the lube line to the dog bone (XY nut bracket). That was a trick and was probably the most difficult issue to resolve on this part of the project. I drilled and reamed a hole where the original lube hole was in the dogbone and then flared a small shoulder on a piece of 1/4" copper tubing - about 3/16" from the end that would end up in the bracket. There is not enough room to use a Legris style fitting without heavy modifications, so I was able to bend the copper tubing into a very tight radius with the use of sand inside the tube and a spring outside. A tight radius was required because of limited clearance to the bottom of the table. I cleaned everything up extremely well (it was disassembled, reassembled two or three times during all of this) and used Loctite #609 (green, cylindrical locking compound) to hold the small copper stub in place and it was staked in place also. Then I connected the plastic tubing to the copper tube with a push to connect fitting. I anchored the tubing inside the saddle by using loom clamps and machine screws - you can barely see one mounted to the front, inside wall of the saddle. There are about 6 of these loom clamps keeping all of the tubes run inside the saddle out of harm's way.

The forth pic is a different angle of the same manifold as pic 3. The location of the pump is going to likely have to change depending on what happens with the drive design (in progress). I spaced the pump unit away from the mounting surface on the knee to prevent chips from collecting near the fill cap. It's located in a pretty good location for access to the handle, protection from chips (because it's under the table most of the time) and for filling....too bad it has to be re-located. I am probably going to mount it under the door on the column.

When I have both main circuits 'on' (selected by the blue-handled ball valves, 5th photo ) I get about 100PSI when I pull the pump handle. It takes about 10 or 15 seconds for it to reach zero PSI. This hits each point with what I feel is an appropriately porportioned shot of go-juice.

In the 5th pic you can also see (barely) the line that goes to the Z nut to keep it happy.

Pic 6 is a view of the few lines run to the right side of the machine. I will clamp the tubes later when I wire the steppers and controls permanently.

Oh - that Trav-A-Dial bracket along with the dials and mounting hardware will be on E-bay soon. I am going to sell it as a complete system with the surface-ground Y axis bar. Should bring in a couple hundred, no? Or should I sell it off in pieces - whaddya think?

Sorry for the long read - I got a little carried away. That's it for tonight. I have to try to get the X drive bracket design complete.

Please ask if you want more specific pictures or info - this sharing thing is cool! It's nice to give something back after mooching free ideas and info for so long!

Scott

[mxtras]

Originally Posted by bill south Scott; What are you going to drive the axis with. Servo's or Steppers and have you sized them yet. I also am interested in a home shop BP mill and will go through the same conversion you seem to be performing. Please keep us posted! Bill from Spartanburg

Bill -

The steppers I am using are pretty hefty - and almost impossible to find specs on.

They are:
Astrosyn
Miniangle Stepper
type 42pm-c022-01
3.6V/phase
4.0A/phase
1.8 degrees per step
made by Minebea Co. (Japan)

5/8" shaft, 4.125" motor diameter. Big. I pulled these (as well as a few spares) from a piece of equipment that I re-designed at Mitsubishi. I think they are still available because the maintenance department had ordered a spare set about 2 years ago. I got those, too....he, he....and rumor has it that there are two more somewhere - total of 6 = 2 machines to me!

I checked the sites for motor specs, but foreign sites suck in comparison to American sites for navigation and information....no results from Google, either. Maybe someone here can point me in the right direction for specs??

These things are probably overkill - that's my guess...very powerful and could likely be used direct to the end of the screws to drive X and Y, but I am going to use about a 2.5:1 reduction to increase accuracy and torque. I am also planning on using encoders for feedback. I am using Gecko drives. My business partner is the guru for the control system - he is awesome with this stuff - seriously impressive. He does industrial controls, interfaces and motion systems for companies like Mitsubishi - he knows his stuff and isn't afraid to play.

I will fill you in with more details of what I end up with when the motors are mounted.

I've included a few pics of the motors. The drive design is not complete, but the last pic shows the basic layout (very poor output from ACAD!). I will post all the details when it's done. One of the smaller pulleys in the middle is the encoder (pulley on an axle with roller bearings), the other small pulley is a tensioner.

It is all being done in ACAD 3D so I will have drawings if you're interested. I also have SolidWorks and Inventor but I am not very proficient at either yet. I have been using ACAD for so long, I am just WAY too comfortable with it.

Keep checking back for more on this project.

I hope I don't irritate anybody with the length of my posts - some are rediculous! Sorry! I try to be accurate and complete....maybe I need to lose the 'complete' part, huh?

Scott