Old 3 in. CIM

Does anyone know anything about the old 3 in. CIM? I heard that they were legal years ago, and then were banned. I have two which I would like to use for household projects but I don’t know much about them. I’m planning to use one to power a small portable lathe but running into issues with power transmission to the spindle. Anything about gearboxes they worked with or motor torque/power curves would be helpful.


If you search cd-media you should be able to find documents with motor specs from 06 and 07 (when they were legal).

From memory they were ~2700 rpm, and about 2/3 of a CIM in terms of power so ~ 450 oz-in of torque.

Andymark used to sell (maybe they have some left?) a 28T gear w/ the D shape for it.

I’d recommend using belt for the power transmission though.

The efficiency and duty cycle on them (like the CIMs) isn’t great, so not sure they’d be a great choice for a continuous duty application like a lathe.

I’ve attached the motor curves for the “Big CIM” from 2006. Hope this helps.


CIM_Motor_FR801-005.pdf (53.3 KB)

CIM_Motor_FR801-005.pdf (53.3 KB)

If it’s for a lathe, you can just purchase a big 120v motor. You would need a really massive 12v power supply if you go with an FRC motor.

Thanks everyone for the info, very helpful. It’s a small hobby lathe for wood turning only, I think the CIM will be ok. Thanks asid61, I have a 60 amp power supply ready for it.

Why do you think the CIM will be okay?
Why would you choose to use a brushed DC motor instead of a basic AC motor?