The file 'M3 Fine Adjustment Knob 3D Printer Model' is (STL) file type, size is 8.9KB.
Tolerance designed for press fit. I used my desk vise.
Prints thinner than most nuts so the plastic won't get in the way. Print 8, add some washers and you have a solid bed leveling system.
thumbscrew.STL | 40.3KB |