Vintage radio knob

thingiverse

This is a replica of vintage French radio knobs that were molded from Bakelite[TM]. The original knob was probably redesigned in OpenSCAD in just a few minutes, as some were damaged. A set screw shaft collar with an M4 set screw is needed to hold the knob tightly on the axis for full functionality. You can use a DIN705A German collar with a 16mm outer diameter and drill a 12mm hole using a lathe, which takes very little time. The original collar has an outer diameter of 16mm, an inner diameter of 12.5mm, and a height of 7mm. A pointed set screw is about 9mm long. Since I was reusing the original parts, all dimensions are for this type of collar. Two test prints have been made with red filament so far, but the destination color will be dark brown/black. Print Settings Printer: Cheap Chinese Prusa Clone Rafts: No Supports: Yes Resolution: 0.1mm Infill: 20% Notes: Kaisertech ABS filament was used at 245°C. Slic3r 1.3 rc8 was used with support for the outer ring only, as inner structures don't need support. Three perimeters and three solid layers were printed, along with top infill that's concentric. Post-Printing Remove Support Remove support from the outer ring. If necessary, sand the surface where the support was removed. Acetone vapor bath Put the knob in a closed container with some acetone to smooth the surface. Let it sit until the surface becomes shiny and smooth. Watch https://youtu.be/Xj53P2YzYGM for a demonstration. If left too long, the knob will become soft and distorted. Add front plate Use a thin aluminum or stainless steel plate and glue it into the cavity on top. Use your preferred surface finish before gluing.