Hand machined mechanical pencils

Knurled thumbscrews using threaded rod (20/07/15)

Yet more knurled thumbscrews using a rope knurl! These have a very low-profile knob (only about 2.5mm thick) and use a piece of M3 threaded rod as the screw. The threaded rod is silver-soldered into a shallow cavity in the brass knob. To ensure that everything lined up, I didn't part the knob off fully so it remained attached to the bar stock with a small piece of material - this limits heat conduction away from the knob when soldering. The threaded rod was held in the lathe chuck and the knob+stock held in the tailstock - this allowed both parts to be soldered whilst maintaining alignment. After soldering and cleaning, the knob was cut off and faced.

Turning the profile for knurling


Cutting recess for threaded rod

Deep groove cut to limit heat conduction

Theaded rod held in place and fluxed

After soldering - sandblast to clean

Threaded holder to turn the other side of the screw