Hi FreeCAD folks, I used FreeCAD to design some replacement parts for some old 1920's Radio Headphones. Specifically the Bakelite ear cup's were broken, so restoring the headphones was going to be a challenge. So I designed some replacement replicas and made 3D Printed replacement parts.
These ear caps were made for Brandes brand headphones made sometime in the 1920's
The ear caps are printed in two peaces then glued together, then sanding, paint and or epoxy the surface is smoothed out to look more like the smooth surface of the original Bakelite parts.
Also a couple files are for 3D printing some sanding arbors, one is optimized for a lathe and another for a 3/8 drill chuck.
I have a YouTube video that goes into the details of making my ear cap replacements the video is at: https://youtu.be/-7h8EQaEMt0
The 3D printing files are at my Thingiverse page https://www.thingiverse.com/thing:3900510
The most notable issue is the threads are very fine and are close to the limit that can be printed with a FDM printer. I found using a lot more fan cooling, bit higher extrusion temperature and much lower print speeds helped the most. It seems also the age of the plastic makes a difference. New is best. They'll still be some light stringing at the threads to clean up.
It may also be necessary to adjust the scale slightly to get the best fit. So several printings maybe necessary to get them to work.
I also have a question on how to generate threads. I used the Sweep function to generate a helix sketch. But to create a solid I could seem to only get a single thread. So to produce more threads I had to clone and then offset the location. It worked, but I seem to be missing something on how to get the solid extrusion to follow the length of the sweep sketch. Any suggestions? Using ver .18
I do other mechanical stuff on my YouTube channel that may be of interest.
https://www.youtube.com/channel/UCtBGrx ... JbA/videos