Are you sure it’s your build? Are you? 
3 Likes
Maybe shave a little off the clamp and reprint? Since it’s over the tube it shouldn’t effect your Z
My tubes started rotating as well. After examining everything closely, I could not tell what the problem was. I finally removed the top clamps from the rails. Three of the four clamps had snapped. The break occured where it was not visible and the part did not wriggle as it was held firmly by the screw. I bet if you take your clamps out you will find the same problem.
I printed those parts with a blue filament that was overly brittle, in retrospect. The filament would occasionally break as I was printing all the parts. I have about 40 hrs on the machine and the vibration had eventually caused the breaks. BTW, the top clamps are a pain to get out as the tubing has to9 slide out off the way before they can be removed, and fishing those small broken pieces out were no fun either.
5 Likes
Good to know. I’ll take a look at that too.
Wow, interesting. Can you share a picture of where exactly it broke?
Sorry, they hit the trash already, new ones printed and in place. The break was in the flat part, not in the curve.