Hermes Baby Typewriter Knob with Guitar Knob collar

thingiverse

This is an exact replica of a Hermes Baby typewriter platen knob (right down to the number of ridges around the edge!), but modified to accept the inner collar and screw from a standard 1/4" guitar knob. This way if you're missing the original metal insert you can still make a fully-operational knob. Any cheap plastic guitar knob with a set screw will do; just search for "chickenhead knob" as that type will have exactly what you need. Break it open, extract the metal collar, and press-fit it right into the new knob. You'll need supports in any orientation but I recommend printing it upright like a mushroom so the upper surface comes out nice and smooth. 100% infill. This should fit on any typewriter (or anything else) with a 1/4" or less diameter rod. The center hole is 8.8mm deep; knob is 25mm diameter x 8mm thick; the whole piece including collar is 14mm thick. An original-spec knob without the guitar collar modification is posted here: http://www.thingiverse.com/thing:2134315