Mostly as an excuse to use the mini-lathe’s MT3 headstock collets, I made a cover for a tuning whistle (it’s an A, if that matters) case that’s been rolling around on the bench for far too long:

Tuner cap – trial fit

Yeah, it needs a bit more polishing and maybe a fancy 3D printed wrapper…

By some small miracle, one of the cutoffs in the brass tubing heap was exactly the right diameter and length, needing only a cap.

A cap looks a lot like a random piece of brass shimstock held in place with silver solder:

Tuner cap – solder setup

Fire the propane torch:

Tuner cap – soldered

I trimmed the shimstock around the tube with scissors, grabbed it in a collet, and laid into it:

Tuner cap – lathe trimming

That’s just before the last few passes bringing the shimstock and solder fillet down to the tube OD, which sat nicely concentric in the collet. The carbide insert worked surprisingly well and produced shavings resembling stringy dust.

The collet drawbar, a.k.a. a hardened 3/8-15 bolt and washer, requires a distressing amount of effort to clamp the collet around the workpiece. I think it wants a Delrin / UHMW washer or some such to reduce the friction; a full-on thrust bearing seems uncalled for.