Lathe to CNC - Microstepping

[creative_mind]

I am in the final process of restoring and converting an old Atlas/Sears lathe to CNC.

I will be using Acme thread lead screws (3/4", 8-TPI and 1/2", 10-TPI) and probably some homemade Delrin nuts.

I have some NEMA 34 bipolar stepper motors rating at 2.35 volts, 4.1 amps per phase. Also, I have some NEMA 23 unipolar and bipolar stepper motors.

I desire to drive the stepper motors by utilizing microstepping drivers.

The question is, will either full, half, or microstepping is the best way to go?

I am looking for answers from experienced CNC buff here that have had the experience converting machines into CNC.

I am uninterested in opinions or theories of how to do it, ONLY actual experiences...no B.S. please.

[HuFlungDung]

Well, I guess I've had actual experience with lathe retrofits I think you are wasting your time. Those motors will be too small and gutless to do anything. A lathe carriage is a significant load in and of itself, and so are the cutting forces. Most likely you will not be able to achieve any sort of rapid speed.

To do useful work, a motor has to consume some power, and I cannot see those ones being large enough to even begin to be useful. What's worse, they are steppers, so they'll be dropping steps like crazy.

[creative_mind]

Hu,

This is the bipolar stepper motor I have now. I hope it's not too small.

Japan Servo KP86SM2-002 Bipolar Stepping Motor
2.35 VDC @ 4.1 Amps, 1.8 Degrees/Step

DIMENSIONS:
Body: 3 3/8" Diameter x 3 3/4" Long
Shaft: 3/8" Diameter x 1 3/8" Long
Distance between centres of screw holes: 2 23/32"
4 Leads

[Stevie]

I have 3 of these too

They are rated at 310oz/inch or 19lbs/inch

[creative_mind]

Stevie,

What did you use to drive your motors?

[Stevie]

I've been busy buying up Parker Compumotor Microstepping drives from eBay; in fact I got the last one tonight (6) total
I have 2 projects going; a Micro lathe and a Mill; the mil is only at the design stage right now; but the lathe is in it's final completion stage "see this thread" http://www.cnczone.com/forums/showth...&threadid=3029
Also see my thread about the compumotor drives in this forum

[cutfinger]

I would suggest you take a trip over to Dave at DAK ENGINEERING, the guy is a diamond, very smart. He developed the TURBOCNC software and he has a lot of experience with stepper driven small lathes. You will find his TCNC group very informative, a lot more "tell" and a lot less "show"
I did a small lathe conversion using steppers and I found that 1/8 microstep drives were the way to go. I never loose steps which was a problem with the 1/2 stepping drives I started out with.

[Ken_Shea]

Hey Stevie,
I am sure I am not alone here, haven’t seen any new post on your CNC lathe, maybe like the rest of us, not much free time

By the way, along with your beautiful work you have remarkably sharp pics as well, what camera are you using?

Ken

[Stevie]

HI Ken

Well it's a Fujifilm Finepix 3800; I still need to build the tailstock; and yes it's busy time again; I have yards to get ready for summer and then the pool will have to be opened again; plus I am fencing off the guys next door; very nosey

Finger; I'm going to use the S6 with matching motor (nema23); and the Zeta4 with matching motor untill i find the right 5phase motor for the Vexta 5114N-E

I got my last compumotor tonight an AX; not sure if it's an L or H
I might need you to tell me how to disable the indexer section of it one day