Was looking for a vfo knob with finger dimple and found the beta Gem Products knob which contains a dimple and a pimple. It was pretty good but is a beta that was printed. I really liked the pimple better than the dimple and so I made my own. Simply took a black sheet rock screw and cut the head off with a dremel and put a dab of goop on the bottom and stuck it on the knob. Works great, very easy to do and easy to remove as good should not damage the knob.

Tried to insert image not sure if that works here...
73 Tex
ka5y