After Raj thoroughly shamed me for slobbering white glop on the KG-UV3D’s volume / power knob, I hereby repent…
Clamp a cutoff chunk of 3/16 =0.1875 inch diameter brass tubing in the lathe and file down one side to put the flat 0.150 inch from the far side, so that the knob is a tight slip fit. If you happen to have some solid rod, that would work just as well. In this case, the file pushed the paper-thin brass remnant into the tubing and I didn’t bother to clean it out:

Clean the white glop off the knob, jam the knob on the fixture, clamp the fixture in the Sherline’s vise, use laser targeting to center the spindle on the notch adjacent to the minuscule pip on the knob:

Drill a 2 mm recess that en passant obliterates the pip:

Fill it with some light gray paint that just happens to be on the shelf:

And, by gosh, it really does dress up the radio! [grin]

While I had the Sherline set up, I did the knob for the other radio, too.
Thanks, Raj… I needed that!