Stock K40 - Stepper motor failed

Hi all,

I have a stock K40 laser engraver.
Y axis stepper motor has failed.
With no power, i should be able to move axis up and down freely.
It seems that it is stuck.

Can you suggest a replacement part for stepper motors.
I want to replace both stepper motors.

My board is stock M2 nano.


How did you diagnose a bad stepper motor?

If the Y axis is hard to move, I’d fist suspect that the problem is a short within the stepper motor driver on the control board.

I turned off the machine completely. X axis was able to move left and right without any problem. Y axis was stuck. Can not be moved at all.

In addition i have loosen the belt and i can not rotate motor axis

I would make sure that it’s still the same if you disconnect the wires from the stepper motor. If it spins freely when you disconnect the wires, the stepper driver chip on the control board is dead; if it is still stuck with the wires disconnected, it’s a physical problem such as a piece of metal stuck in the motor bearings.

Specs at:

Also, this might be of interest:

Thank you for the info.

I have disconnected stepper motor completely and it is still stuck.
Do you know where i can find a replacement?

Don’s post shows what you are looking for. NEMA17 motors are everywhere these days because of 3D printers. He has X and Y specs, including size and electrical specs. Make sure that the body length isn’t longer than what you are replacing; shorter is generally OK. You’ll want inductance to at least be similar, current capacity to be no less, don’t worry about voltage rating per se because it doesn’t matter in this application really (though it’s related to inductance).

The only meaningful physical spec variation I’ve seen is some NEMA17-advertised motors I have seen have #4-40 screw threads instead of M3. That seems less common these days, probably in part thanks to 3D printers.

Make sure the motor is 0.9 degree per step. That is what the K40 uses, not the standard 1.8 degree per step motors that 3D printers use. The stock board is setup to use 0.9 degrees per step in the firmware.


I missed that, thanks. @Dimitris_Galaktiou, note that 0.9⁰ per step can also be listed as 400 steps/rev. Some 3d printers use 400 steps/rev for some stepper motors, but it’s definitely a niche.

Exactly where is a best source for you depends on where you live, I guess. Shipping across the ocean is taking a long time right now due to COVID-19.