Stepper gear - this probably isn't supposed to happen

My X-axis gear started slipping today. I had tightened the set screws before when assembling the machine and noticed that the set screw that seats in the groove on the stepper motor shaft isn’t really long enough. When it’s tightened down, it is only hanging on by a thread or two. Well, today it worked itself free and my gear started slipping.

I had trouble pulling the gear off of the shaft and when it did come free, the washer that is press fit on the back of the gear came off. >.<

Assuming it doesn’t just press back together, how do I order a replacement and maybe a longer set screw?

I pressed it back on. What do you think my chances are that it will stay? :smirk:

…off to the hardware to see if they happen to carry a longer set screw that will work.

from memory you might be able to swap this one with the Z Axis motor as a temp solution… There is less room for the belt to move.

The set screw should go all the way into the hole - assuming the gear is on correctly there would be no where for the set screw to go, but hold it in place

1 Like

There’s a bit on this here:

The set screw should be an M3 which you can get at any hardware store — I bought my pulleys and belt from sdp/si: and

1 Like

At first I was concerned that the flange came off during operation - which would mean the belt was pulling against the flange. (this would only happen if the pulley was not in alignment with the belt ends.

Although I prefer the longer set screws - those shorter ones work just fine.

Loctite does not appear to be on those threads -

1 Like

I have it back together now and put a drop of Loctite on there this time (I honestly wasn’t sure what parts I was supposed to use it on as my axis plates came pre-assembled; I just checked that everything was tight and bolted the rest of it together). I think I am going to get some longer screws though… I’m afraid I will strip out the thread if I really tighten these. May not be needed, but also shouldn’t hurt, right?

They ship with loctite now.

Longer screws wont be needed.
The Hex or the wrench tip may strip - but the threads wont.

Just snug it.