After one too many session opening the base of my Thing-o-Matic and having the hex nuts fall out of the t-slots, I decided to do something about it. This design should hold the M3 hex nuts firmly in a t-slot, while still making them easy to remove if possible. The bottom of the holder also serves to spread the force from the nut to reduce potential damaging effects of compression on the wood.
Because the object is small and the tolerances are pretty tight, the printing can be a little finicky. The included OpenSCAD model contains commented parameters that should make adjusting the object pretty easy.
I have only printed this in ABS. It is very important that you print the holder with an infill of 100%. Otherwise the bottom layer tends not to be solid.
I've had good luck printing with a thickness of 0.2mm and a width/thickness of 2.
- Print a holder
- Insert an M3 hex nut into the hole with flats parallel to the long sides.
- Insert the holder into a t-slot with the bottom between the nut and the incoming screw.
- Tighten the screw.