Making a knob for the Saffier

This project first appeared at @ma3ke@hachyderm.io on 2025-05-26.
This article was created on 2026-06-09.

On the Saffier, a threaded knob is used to clamp the slider for the boom to the mast. Its old, brittle plastic has worn and broken, and it is very hard to turn with the necessary force due to its sharp edges.

Let's make a new knob on the lathe!

the knob is used to clamp the boom to the mast

the original broken knob held next to a piece of aluminium in the chuck of a lathe — I started out with this slightly smaller diameter aluminium rod.

On this lathe, I find parting off works quite scary. After parting off, I cleaned up the other face.

spinning lathe head with the piece being in the process of parting off — After placing it back in the chuck, I used a dial indicator to make sure it’s concentric. Not actually necessary, as this face is purely decorative.

I’m holding the cut-off part in my hand — After placing it back in the chuck, I used a dial indicator to make sure it’s concentric. Not actually necessary, as this face is purely decorative.

I did a successful test fit.

I decided to file out the four recesses to provide grip.

four recesses are filed out on the rim — It looks nice and soft after polishing.

polished and softened knob — It looks nice and soft after polishing.

It looks very pretty! Sadly, it is still not very easy to use and to apply the needed force, especially for my mom. Creating a second version from a larger diameter material should be the next step.