About this 3D model
I didn't really like the rather hard rubber surface of the original knob and wanted a crank anyway, so I made a crank knob and a fitting Oogoo mold to make a softer rubber sleeve for it. I also included an STL of the rubber sleeve if you want to try printing it with flexible filament. The diameter of the sleeve is 1 mm smaller than the knob to create a tight fit. Update: This thing is featured in the August edition of the DARC (German Amateur Radio Club) magazine CQDL: http://www.darc.de/cq-dl/