Here are the blanks along with the prototype stop knob I made.
The knobs are walnut and the face plates are maple:
Here's a series of photos showing the turning process:
My sister has beautiful hand writing so I had her print the face plates for me.
I tried lots of pens and found one that worked well as long as I polyurethaned the surface first.
Here's my sister and her daughter at work:
Here the stop knobs are being glued to the shafts with a level to check rotation:
Here are the shafts and stop knobs after a coat of polyurethane:
Here are the completed stop knobs: