Quick post, more pics than words.
Not shown: removed overhanging inlay pieces with flush cut saw, cleaned up the edges with a chisel and then sandpaper on a flat surface. Then, marked and drilled indexing holes for the jig.
Next built the jig for drilling. It is basically a base with an indexing pin, a fence, and a marked point to line up the drill. This is it from the back side. You can see the white indexing pin from this view.
The work piece was thicker than the height of the final knobs, so a pass was done with the saf-t-planer on the bottom side,
then flip it over,
and take a pass on the top side, so that the padauk thickness will match the thickness of the fingerboard exactly.
The first drill of each cycle is a 5/8" forstner,
followed by a 1/4" for the pot shaft.
There you can see the tool I used to check the depth of the forstner counterbore. The tape on the drill bit is for depth on the pot shaft hole, but it also worked out to be a case of drill until you see "blood" (padauk). The bit has has the brad point ground down to just a bit longer than the cutting rim.
Next is the tenon cutter. Here it is lifting out a knob that was just cut.
The tenon cutter was running very hot, and even stalled out the motor on the the first few cuts. The first knob broke off short of full depth, and was ruined.
After the fifth knob, I took off the cutter and examined it. I then got out the files and changed the geometry on the cutting teeth. After that it ran much cooler and did not bog down. Also the first knobs had purplish burnt padauk bits embedded in the maple. The second five came out clean.
Here are the nine drilled-out pieces.
After that I did the dome shaping, just as on the string anchors. The difference this time was that the knobs were pressed onto a steel dowel pin that was in the chuck.
The first four knobs, with dome and smoothed.
Next will be putting the tapholes in the sides.