Hermes Baby Typewriter Knob with Guitar Knob collar

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 i