by alasdair53, published
I lost the knob for a random consumer electronics thing, and I thought I'd print a new one - well, you know how one thing leads to another, usually an SCAD script, in my case.
This is a snap-on knob for a shaft with a flat - there's an internal stress-relieving slot that helps the thing absorb the strain of pushing it onto the shaft.
Measure the shaft you want to slide this on - my shaft had two portions, with slightly different diameters. The flat is on the top half (!). The awkward +0.5's are a way of compensating for my Makerbot's printing holes smaller than I'd like. (But see http://www.thingiverse.com/thing:6118 and assorted blog post http://hydraraptor.blogspot.com/2011/02/polyholes.html)
Measure or calculate or guess the height of the knurled section you want (this is the bit you hold with your fingers).
Decorate the bottom, if you wish, with a skirt.
For real added credibility, add a dome on the top. Don't be excessive.
Enter the parameters to the beginning of the script, run it, and print the resulting stl.