Knob for socket cap-head screws in M3, M4 and M5

thingiverse

This is a remix of my M3 screw knob design that seems to be quite popular. I have tidied up the code, made it more reliable to print, and expanded it to cover M3, M4 and M5 socket cap screws. It comes in two flavours: using either a standard nut, or a nyloc nut. In the pictures, the white knobs have standard nuts, and the red have nylocs - note the slightly greater height. The standard nut is easy, and usually very secure. If you feel the need for a more reliable knob then you can use a nyloc nut - but be aware that it is a struggle to fit onto M4 and M5 (M3 is fairly easy). I recommend that the nyloc nut is wound down as far as possible using a spanner/wrench, then pushed into the hexagonal cavity and the screw wound home; the problem is that it's very difficult to hold onto the knob at this point. It will be necessary to hold the outside using a vice or pliers during this process, while trying not to damage the surface. If you want a secure fixing without the hassle, I recommend using a standard nut and some thread-locking fluid. Parameters such as knob diameter, number of grooves around the outside, and so on can be easily changed in the OpenSCAD code.