Primo Core Tension

Hello All,

Trying to build a Primo, and got to this step. My core is very loose on the rails prior to adding the nuts. Not all the bearings make contact, and the rails wiggle back and forth. Any tips for troubleshooting or fixing?

Here is a picture of the area in question

Ok, first question, what rails are you using and are the printed parts for the correct rail diameter? Mine uses 3/4" emt. I found when i set mine up using v1 purchased printed parts, I had to tighten the nuts slightly to make all bearings touch the rails. Once you have them all touching, you’ll need to check them every few months. I’ve had some of the bearings loosen up. Always check for cracks first if finding loose bearings. I haven’t had any cracks, but figured I’d throw it out there.

Yup using the EMT conduit. Ok, glad to hear that it is normal to have to tighten the bolts before the bearings touching. And thanks for the tips on routine tightening and cracks.

I have broken the attaching parts 2 times so be careful it is hard to see sometimes. But it is easy fix and well worth i just have the ability to use a cnc :smiley: the first set was over tightening the second set lasted till 8 months ago and had been retitened one to many times