Vintage radio knob

thingiverse

This is a replica of the radio knobs found on a vintage french radio. The original knob was molded, probably Bakelite[TM]. As knobs were damaged, I redesigned the knob in OpenSCAD in a few minutes. To be fully functional, a set screw shaft collar with a M4 set screw is needed to hold the knob tight on the axis. You can use a collar with german DIN705A with 16mm outer diameter and drill the hole to 12mm. Using a lathe this is done in very short time. Original collar outer diameter 16mm, inner diameter 12.5mm, height 7mm. Pointed set screw length about 9mm. As I was reusing the original parts, all dimensions are for this type of collar. Currently I have made two test prints with red filament. The destination colour is dark brown/black. Print Settings Printer: Cheap chinese prusa clone Rafts: No Supports: Yes Resolution: 0.1mm Infill: 20% Notes: Used Filament Kaisertech ABS 245°C. Slic3r 1.3 rc8 Support for outer ring only, inner structures do not need support. 3 perimeters, 3 solid layers, top infill concentric Post-Printing Remove support Remove support from outer ring. Sand the surface where the support was removed if necessary. Acetone vapor bath Put on a support in a closed container with some acetone to smooth the surface. Let it smooth until the surface gehts shiny and smooth. See https://youtu.be/Xj53P2YzYGM for a demonstation. If you leave it too long, the knob will get soft and distorted. Add front plate Use a thin aluminium or stainless steel plate and glue it into the cavity on the top. Use your favourite surface finish before glueing it.