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lathe motor conversion?
« on: March 05, 2015, 09:22:30 PM »
I have a sherline 4000 lathe CNC, 36v power supply , C10 board, 2 keling KL-4030 stepper drivers , 2 150oz stepper motors and of course mach3, everything works great. However: I want to get rid of my lathe motor and replace it with a nema 23 DC servo, timing belt and pulley's to be able to do threading and turning. Is this possible to just add this to what I have, or do I need to get a whole new set-up? I've asked around online with no answers.

Offline Hood

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Re: lathe motor conversion?
« Reply #1 on: March 06, 2015, 03:44:48 AM »
You only need an index pulse to do threading, no need for a servo. Not sure what you mean about needing a servo to do turning.

Hood
Re: lathe motor conversion?
« Reply #2 on: March 06, 2015, 06:34:39 AM »
Ok, So will a index pulse be able to hook up to my orginal motor, or will I need to look at something else?

I see that the servo motor will do 4000 RPM and is brushless. My original motor's bearings are going bad so i thought It would be a good replacment.

Offline Hood

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Re: lathe motor conversion?
« Reply #3 on: March 06, 2015, 07:44:11 AM »
For Mach to do threading on a lathe it does not have to control the spindle speed. All it needs is an Index pulse so that it knows how fast the spindle is actually doing.
 Normally for an Index pulse you use a slotted disc and an optical sensor and have the disc fitted directly to the back of the spindle. Some people also use a magnet and a prox sensor.
If you want control over the spindle speed then the servo may be the way to go.

Hood
Re: lathe motor conversion?
« Reply #4 on: March 07, 2015, 06:25:34 AM »
Thanks

Offline RICH

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Re: lathe motor conversion?
« Reply #5 on: March 07, 2015, 07:40:27 PM »
I have a wee Sherline and the motor is punny, but if you don't tax the machine it can do nice work using small cuts.
Also you may wnat to try alternate flank threading as that helps with the cutting of the thread.
I have done threading on it sucessfuly. From 0-80's to maybe 1/4-20.  The 150 in oz on mine were replaced with 350's I think.
The speed control on the Sherline is not all that great.....once set it would vary some +- 2 rpm and slowdown is expected on threading.
Get too much slowdown and the thread may be trashed!
Also have the anti backlash kits installed and that works well but need to check and adjust them. Used a blalk painted CD rom for the index disc with
a slot  bigger than recomended.

FWIW,
RICH

Offline BR549

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Re: lathe motor conversion?
« Reply #6 on: March 08, 2015, 09:05:51 PM »
IF you already have a decent servo there is NOTHING  sweeter running  than a Servo spindle Lathe. I think I would start at a full blown Nema34 rated at +3000 rpms  AND make sure it has a STEP/DIRECTION servo drive . That will keep it all simple AND make a sweet running machine with enough power AND spindle sync to make perfect threads every time.

Just  a thought, (;-) TP
Re: lathe motor conversion?
« Reply #7 on: March 10, 2015, 03:07:10 AM »
I'm looking at this NEMA 23 Closed Loop Stepper Motor System-Hybrid Servo Kit, 32 bit DSP Based automation technologies inc. Would you suggest this?

Offline Hood

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Re: lathe motor conversion?
« Reply #8 on: March 10, 2015, 06:21:40 PM »
Would stick to a servo personally.

Hood

Offline BR549

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Re: lathe motor conversion?
« Reply #9 on: March 10, 2015, 06:46:42 PM »
Stick with servo, Nema34 highest torque you can find.   NOPE on the hybrid.

(;-) TP