M3x10 screws too small for core

Mostly Printed CNC - MPCNC Troubleshooting
1

I’m building the MPCNC Primo and very much enjoying the process. Something I’ve come across while attaching the nut for the T8 lead screw to the core, is an issue with the size of the holes for the M3x10 screws. The screws themselves appear to be fine; they fit perfectly in the Nema stepper motors and a check with the calipers shows them to be 3mm in diameter. At first I thought it might be my printer, however checking the source STL shows the holes in the core to also be 3mm, which means the screws will not grab the insides of the holes. I could use loctite, however I’m concerned that the constant up/down motion will quickly break it loose. I could use something stronger, but then I’d never be able to get the screws undone.

Help.

2

I stripped out my burly screws for the T8 nut. My solution was to swab the inside of the holes with gel super glue and let it fully harden. It did a couple of rounds before reassembling.

3

FWIW, the nut will be held in place with gravity on the spindle. The screws just keep it from rotating. You could probably drop them in and be fine, but glueing them, or locktiting them or hot glueing them should all be fine.

4

Thank you. I will try the locktight solution. Hopefully there will not be significant upward pressure when I drop the bit into the material.