Right trapezoidal nut too tight
The right trapezoidal nut was so tight that it completely prevents the right Z-axis motor from working. At first I thought perhaps it was a bad motor or cable, but when I remove the trapezoidal nut the printer works fine (other than the right side hanging down a bit). So I'm sharing that in case it's useful to anyone else.
So I'd like to replace it. It's not a printed part, but I did find https://www.thingiverse.com/thing:2246502 which is for the Mk2. I figure I'd give it a shot (Nylon is cheap) but I'm not sure if the Mk2 and Mk3 are the same for this part. I'll know more tomorrow. Though I imagine a non-printed nut would be more reliable in the long run, I just got my Mk3 assembled, and I'd love to get it productive sooner rather than later.
Re: Right trapezoidal nut too tight
I had a similar problem. I rotated the nut and used a different set of screw holes on the trapezoidal nut. I also used a little bit of silicone based lubricant in the nut. This fixed the issue and I got my first prints out today.
Re: Right trapezoidal nut too tight
I have just run into this on my Mk3 kit, it is so tight it is impossible to thread the screw into the trapezoidal nut. Turning the nut in the mount didn't work either. I even took it completely off and tried to thread it on to no avail.
I have sent in a request to support for a replacement.
Time to wait some more.
Re: Right trapezoidal nut too tight
To follow up, based on recommendations from discussions here, I unthreaded and rethreaded the nut repeatedly, trying to make sure that it wasn't cross-threaded. Each try got a bit easier, until eventually the nut moved fairly freely, and the printer worked better - the right motor was "laggy" but not completely stuck. Then I did a few Z-calibrations, so the motor ran the whole length of the Z axis, and the nut is now working fairly smoothly, and printing is working well.
My guess is that I must have cross-threaded the nut the first time I threaded it, damaging the plastic threads in the nut, and then re-threading it wore the plastic down into the proper shape.
Thanks for everyone's help!
Re: Right trapezoidal nut too tight
Exactly my problem too. Right nut - very tight on the motor out of the box. I have tried to clean up the thread and used a bit of grease but it is not coming loose.
Chat said I will need to email support which I did a day ago. Still waiting to hear back from them.
Re: Right trapezoidal nut too tight
I have the same issue. It's only one of the nuts that's too tight. The other one is fine.