View Full Version : Pro and cons of treadmill motors etc.

06-16-2004, 05:45 PM
I'm working on the design of my CNC mill. Iv'e been looking at surplus treadmill motors to power the spindle. They look like a good deal and I am looking for high RPM which they have. I have never played with one so what should I be aware of when looking for one? Any one know what sort of speed control the treadmills use? I would build a PWM controller if I must.

Next question. How much of a mill table can you move with a NEMA 23 stepper with 280 in/oz of torque and a chopper controller? Anyone familiar with this controller and the outfit selling them? Also looks like a good deal.


I found a guy in WA selling new NEMA23 280 in/oz motors with double shafts and encoders for $45 USD. Also seems like a good deal. Some very good prices on NEMA34 motors too.


Anyone deal with him?

06-16-2004, 05:56 PM
One of the best groups for this type of info is...


Great bunch of guys with tons of knowledge.

I remember there was a discussion on treadmill motors, can't remember the result.

Tom M.

John Stevenson
06-16-2004, 06:36 PM
Dan is a good guy to deal with. You won't have any problems and those motors are a steal.

John S.

06-16-2004, 08:15 PM
The treadmill motors I have several of,I should have bought more when they were cheap.I got one that came with a full blown SCR controller for $50.00,works great,I have another that I used for the welding positioner at work that I used just a variac and a full wave bridge for,it too works good,but more primative.

They are pm motors,so a person of your skills could easily build a controller.Mine have a 17mm straight shaft and a 14 mm left hand double start threaded end(guess what got cut off)I took it apart and turned the shaft 5/8" with a 3/16 keyway.They use a ball bearing on both ends,mine came with a stub stuck on the brush end of the motor,I beleive it was 5/16"x 3/4" long,I assumed this is for a cooling fan,and judging from the amp ratings(28@90vdc)it needs it.

All in all they are great little motors and used to be cheap($12.95)until everybody caught on.They really excell at providing lots of power in a small package.
I did mount a small plastic fan blade and made a shroud out of a pvc cap,I also used a piece of furnace filter on the business end to keep the errant chip or two from getting in(the motors are open end for end).

06-16-2004, 08:33 PM
The 2hp motors, there is one spot in Canada that sells them for 24.95 american money..

There is one guy on ebay been reselling them for $50 a pop.. I hear tell he is in a wheelchair and made 100k last year.

About $30 is a good price. They are mostly not a 1.0 duty factor motor. Meaning don't run them at full nameplate power too long.
My old craftsman table top drill press was acting up today, I may be looking for a similar motor. I ran it as a cnc for about a year. Meaning it ran most the time.

Check ebay for battlebots the PWM controllers on there, you can't build one so cheap, already on a huge heat sink..

Seems like mach2 can output a pwm for spindle speed control.


[This message has been edited by ibewgypsie (edited 06-16-2004).]