X axis moves about 1/16 inch when motor locked

Here is a problem I have not seen before. I got my X motor replaced with my new NEMA 23, I was testing everything and adjusting the controller output voltage for the new motor when I noticed that even when the motors are locked I can still move the X carriage about a 1/16 of an inch. The motor pulley turns a few degrees and then is stopped solid.

Why would the motor have that little bit of play? All the other motors are locked solid with no play at all when they are engaged. Only the X is acting strange.

Any ideas?

My first guess would be a loose set screw in the pulley. See if the shaft and pulley move together when you see the slip.

Does the slip occur moving in one direction only or does it happen moving either way?

Is the new stepper from Inventables, or another source?

Did you have a problem with the original motor or did you just upgrade to get more power?

Hello Larry,

I was thinking the same thing, that the set screws may be a little loose. So I went back to the machine and checked them. Both set screws were as tight as the little allen wrench could get them and one was sitting right on the flat were it belongs.

I turned on the motors again and tweaked the voltage up just a bit for the X and I heard a distinct click and the X motor click and then it was locked (no play at all). I ran it back and forth a few dozen times to be sure it did not cutout from thermal overload and it seems fine now.

I had never seen that happen with the NEMA 17 motors before, so maybe the 23’s can’t lock on a microstep if the voltage is slightly low?

This was not a motor from Inventables, they did not have the 23’s in stock so I purchased this one on Amazon

Allen, do you like the new motors? Should make changing bits during a project much easier… No danger of moving the spindle.

Actually, it’s true that any stepper motor will not be able to supply sufficient holding torque without appropriate current in the coils. I didn’t think about it at the time, but certainly the NEMA 17s would operate at a lower current setting than the 23s.

The new motor has plenty of torque it should work well.

If you are using the gShield a good “ball park” setting for the current limit potentiometer is about the 11 o’clock position for the NEMA 23s.

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It really does hold much better! But it is a real pain swapping out that X motor (without taking the rails apart)

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Yeah, that’s why I went with the 23s right up front.

I had no idea that when I bought my original Shapoko 2 I would get so addicted to it! I thought spending $700 for a hobby machine then was was a crazy amount of money. If my wife knew how much I have spent since then on this “hobby” there would be trouble.

LOL, thanks. Now I have one more thing to worry about.