About this 3D model

This is not a thing that anyone else is likely to need. I'm putting it up here just as one of the examples of the utility of 3D printing for specialized objects. This object replaces the spindle knob on our LPKF printed circuit board cutter. The original knob is small and difficult to grip. It's used to tighten the spindle collet holding the milling and drill bits. If it's not tightened fully, the bit can fall out, destroying the board being milled, and very possibly damaging the machine (has happened to the tune of several $K). This replacement knob just clamps over the existing odd-shaped knob.