Prusa MINI silicone mod (https://github.com/bbbenji/PMSBLM) requires very uncommon M3 locking nut with height 3mm max. You can print it! It makes outer dimensions M4 so you can use standard wrench for tightening.
How it works?
1)Typical M3 nut has height about 2.4mm, therefore you can add 3x0.2 layers for locking the thread and still pass 3mm limit
2) It creates bigger friction surface
Printed in Nylon, 0.2mm layers
The nut requires a bit of force to cut the thread. Mind the nut orientation, it's important (frame, 3D printed nut, metal nut).
The author marked this model as their own original creation.