[wrastu]

I recently bought a 940M from Precision Matthews (with hardened ways), so far I am impressed. I will be converting it with the help and advice from a friend who knows far more than I.

I have been a conventional machinist type for 35-40yrs, but a hobbyist for the last 25yrs since I work outside the trade now.

Anyway, running the 940M thru the travels while cleaning the shipping grease and grime I found the travels to be different than actually advertised.......it was a pleasant surprise.

I am getting X= 33-1/4, Y 15, and Z 21-1/4, with 5.250 on the quill. Granted these are extreme numbers but X= at 32 Y at 14 and Z at 21 are safe everyday numbers, and far more than I will probably use.

I have a HF ZAY7032G that I have been using for the last 15yrs (and 2 (X) longitudinal travel nuts later) and I modified it to get 10" on the Y axis but the 17 on the Z was just to small hence the 940M purchase to convert.

Just wanted to chime in for those looking for a nice machine, you might want to check them out.

I will post a pic now and then as I go thru this if anyone is interested.



Before anyone asks, I made the base for the stand to sit on, it weighs 500lbs+ and the factory stand is about 300lbs, with the machine its about 1800lbs.

I don't like to hunch over when I work and don't do real large pieces, plus I want to use servos with possibly some fast rapids and don't want the inertia moving the machine, and the base just seemed a bit narrow.

I will be building an enclosure also.

Stu

[thecleaner]

Amazing job with the base! Are you gonna stand on the base as well while operating the machine?

I received my PM940 a couple days ago too..guess they come from the same batch.
Mine has a couple minor glitches I can easily fix, but what left me a bit perplexed is that although I got the hardened ways model, they don't seem that hard at all.
Just wiping off the factory grease with some dust it collected was enough to leave some marks. I then did the classic test with a file, and I could easily leave a mark in a corner by applying a very small amount of pressure.
I also have a grizzly lathe and its ways are apparently harder by comparison.

I'm planning my conversion too, will follow your thread closely!

[wrastu]

Amazing job with the base! Are you gonna stand on the base as well while operating the machine?

I received my PM940 a couple days ago too..guess they come from the same batch.
Mine has a couple minor glitches I can easily fix, but what left me a bit perplexed is that although I got the hardened ways model, they don't seem that hard at all.
Just wiping off the factory grease with some dust it collected was enough to leave some marks. I then did the classic test with a file, and I could easily leave a mark in a corner by applying a very small amount of pressure.
I also have a grizzly lathe and its ways are apparently harder by comparison.

I'm planning my conversion too, will follow your thread closely!

No I won't stand on the base, once I get the Y axis servo mounted and the enclosure I should be okay getting in and to the table, if not drill a few more holes and move it forward. (I build bikes so I do a full mock up before final assy as habit)

I too did the file test on a corner, it is a bit harder but not much, I will find out when I put on the oiler and ball end mill some oil groves to prevent stickion with the servos.

As I was in the column today taking measurements for the Z axis ballscrew I noticed there are piles on slag, gonna have to run the shop vac in there and get it clean.

Think I am going to stay with the ways until I see how they wear and not go linear rails right off the start.

Would be interested in your conversion as well.

Stu

[wrastu]

Cleaner,

Update on the build, DMM servos 750w, also got a 3450rpm 3 phase motor and a LSIL VFD, single phase to 3 phase inverter, I have a RPC but don't want to run a 30hp RPC for a 3hp motor, I use the 30hp for running my 10hp lathe.



I got a Centroid Acorn and the Pro Mill software in an Intel NUC, with a 27" Dell touchscreen to go with it.

Waiting on ballscrews, and started tonight on the oil grooves to relieve stiction with the way oil, only got one side done, still need to do the other side, and the column slide also.

Once the ballscrews are mocked up I will do the one shot oiling system and build the servo mounts, I am going to be able to overdrive the X and Y axis to use all the travel I can squeeze out it for light bulky stuff.

Going to have program, proximity sensors and hard stops on the axis.

Here is the stiction reducing oil groves.





The grooves are .050 deep made with a 1/4 HSS ball end mill, first pass was .030, finished at .050 deep.

Got the column off and tearing it apart.



Have the stock on order for a flange to mount the motor.

Acorn board has a hook up for an encoder to control the spindle speed via the VFD.

Going to order a hollow thru shaft and use it on a plate mounted on the bearing cap for the top bearings on the head, then make another plate above that for a air powered drawbar.

I am going to lock the quill in the up position and use the servo driven column for the Z axis. The quill will be lock via the side lock, the hand crank, and a nut tightened down on the quill feed indicator so it can't be messed with. We will see how that works.

The original motor was a 1750rpm 2hp, replaced with a 3hp 3450rpm, so I should be able to get 3000-4000 at the spindle in high range without over driving the motor should I replace the spindle bearing with higher speed bearings and over drive the motor 150-200% I should get 5000-6000 rpm, but thats another project for another day.

Well back to work.

Stu

[jhop28]

We must have got the same shipment as I received mine 3 weeks ago also. I ordered with hardened ways also and all power feeds . The z axis is a little slow but sure beats cranking it lol

[wrastu]

I bet we did, I didn't get the power Z and mine doesn't have the separate power box. The rest of my wiring is coming out anyway.

I think the 2hp will end up on my 16yr old ZAY 7032G (HF), and it will end up with linear slides, a home built column instead of the post, and ballscrews and servos also when the Bridgeport I got a line on shows up. The travel is way smaller but it will be practice for when I eventually do slides on the PM940M

Stu

PS, I know one thing, the Chinese never met a burr they would take a file to. If it can't be hit with a grinder it don't get taken off.

[thecleaner]

PS, I know one thing, the Chinese never met a burr they would take a file to. If it can't be hit with a grinder it don't get taken off.

LOL true!! Some of the ways on my machine leave a lot to be desired, and they've met the grinder too..


nice job with the oil groves!
What's your plan with regards to the Z axis bearings? Are you going to install the bearings inside a plate on top of the column and hang the ballscrew, or are you going to reuse the original bracket and support it from the bottom?

[CL_MotoTech]

Cool project. When I was doing my Grizzly Mill the 13th time I think I filed and sanded on basically every part before I was done. It's much nicer to work on now.

p.s. bikes or bicycles?

[wrastu]

Cool project. When I was doing my Grizzly Mill the 13th time I think I filed and sanded on basically every part before I was done. It's much nicer to work on now.

p.s. bikes or bicycles?

Motorsickles

Stu

[wrastu]

LOL true!! Some of the ways on my machine leave a lot to be desired, and they've met the grinder too..


nice job with the oil groves!
What's your plan with regards to the Z axis bearings? Are you going to install the bearings inside a plate on top of the column and hang the ballscrew, or are you going to reuse the original bracket and support it from the bottom?

Cleaner,

Going to hang it and make a bracket for the double nut 3205 ballscrew.

I got the Y axis moving and sliding, working on the servo mount now .....making my own.


X axis ballscrew mounted, had to machine the underside on each end to over drive the table, got stock on order for the ends.

I will try to get some pics posted soon.

Stu

[wrastu]

jhop,

How do you keep your shop so clean?

Mine is always a wreck.

[thecleaner]

I was thinking of going with a double nut 2505 for the Z and single nut 2505 for X and Y. But after reading you I'm considering a 3205 for the Z as well.
Where are you buying your screws from?

Are you going with AC bearings? What size and configuration? Are you going to pack them into the motor mount plate?

Looks like you're not sparing a penny on this build, it's gonna come up pretty impressive.

Looking forward to see your pictures!

[wrastu]

I was thinking of going with a double nut 2505 for the Z and single nut 2505 for X and Y. But after reading you I'm considering a 3205 for the Z as well.
Where are you buying your screws from?

I got ball screws from two different sources, the nicest and best service with great communication was from Fred at BST Automation.

His email is [email protected] and his store is can be found by googling BST Automation.

You won't see everything he can get on his store site, I emailed him with a request for a quote, his prices were the best and he communicates well and often via email.

Stu

[wrastu]

Looking forward to see your pictures!

OK, before and after of the Y axis.

I used a carbide burr bit in a rotozip and clamped a 5ft aluminum ruler for a guide, cleaned up the slag and overflash of the casting and opened up the width to about
3-1/8

[wrastu]

On the X axis you will have to mill the old mount and make a flat for the ball nut mount.

On the Y axis it is a bit off center and I wanted the mount and angular bearings further out so I could over drive the axis a little bit. Hence the clearance hole.

[wrastu]

I had to make a flange and a shaft bushing to adapt the 3phase 3 hp motor to the mill.

[wrastu]

Angular bearing mount and servo mount, the top of the servo mount plate will double as a mount for the bellows I have yet to buy.

[thecleaner]

Very nice!

I'm going down a similar route. I'm ordering screws and supports from BST as well. The main differences between your setup and mine are that I'll use steppers, won't overdrive the Y axis and will use FF blocks, whereas you're using BF.
I'm doing dual nut 3205 for Z and single 2505 for X and Y.

How long did you order your X axis screw? I calculated 1010 mm of threaded length, 1000 mm is the table length, plus 10 mm is the recess in the fixed block before you reach the bearing. Added 108 mm for the standard machining at both ends, for a total of 1118 mm.
I'm not sure I should account for the recess though, cause the block might come with a spacer, so that the shoulder of the thread on the screw could be flush to the block face.

Keep up the good work!!

[wrastu]

Cleaner

FF vs BF....yeah I was having a spell of cranial rectitus when I ordered, not waiting for new ones, gonna be covered by shields anyway. I did drill out the holes to use 1/4" bolts, everything I replace or alter gets inch/imperial/sae/uss (whatever its called) I am not real metric friendly but I am learning however.

How long did you order your X axis screw?.....1500mm overall machining included in that length. I have the stock for the ends on order and will do them manually, bunch of work on them planned. If all else fails I can shorten and machine the free end.

I made my own block for the Y axis.....used a ready made on X (we will see if it holds up)

I'm not sure I should account for the recess though, cause the block might come with a spacer, so that the shoulder of the thread on the screw could be flush to the block face....If you talking about the FF / BF...my BF the thread shoulder is pretty much flush with the spacer/bushings provided. If you're talking about the ball nut block you will need to make a flat and go only deep enough to make the flat and you should be okay.

DANGER WILL ROBINSON DANGER: On mine the bottom of the table had to be machined to allow the table to slide back on without having to tilt it to clear the ball nut holder. The area on each end WILL hit the ball nut holder and you could use them for hard stops if like bending up your ball screw assy. I didn't bend anything but found out while hefting the table up there to put it back on. I called friend after that and the hefting was team sport then. (You do know who Will Robinson is don't you?)

Got my custom made encoder Friday, gonna work on a mount, plus a base for the servo speedy air draw bar today until I run out of material.

[wrastu]

Cleaner,

Working on the encoder mount and prep for a Servo Speedy Air Power Drawbar.

If you do any work on the top you will find they are masters at body putty. However while it looks cool, it ain't flat by far. Not knocking the machine just saying be prepared to work around it.

Encoder,

Putty removed, not flat and I am not taking the top off to machine it flat.

So what to do? The bolts that are countersunk that hold the top on were drilled at the same depth regardless of how uneven the top was.
SO, the countersink happens to be the same size as the pilot hole for a 1/2 SHCS countersink, shortened the pilot on the grinder and spotted the 4 holes and now they are the same height above the base the top bolts to. Verified by measuring the flat where the bolt bottoms out. Even though I used a hand drill to spot them they are close enough that now I can make stand offs to mount the air drawbar changer. I will make them stepped and use a piece of ss metric all thread to go all the way to the mount plate which will also have a step to go in the plate. Once tight it should hold, the stand offs will be about .800 in dia.



Hope this helps if your doing the top of yours with the need for stand offs for a air drawbar.