Coming Together: My DIY 5" Thumbscrews

I am still waiting for the 1/2" diameter thumb nuts to arrive and the blackening agent but I was able to:

1. Drill and tap a 6-32 hole in the collar.

2. Retap the 10-32 screw to correct for marring caused by the tapping.

3. Turn in the 6-32 x 3/16" set screw.  First I discovered that although coming from the same drawer at Ace Hardware, at least one was flat screw head.  Do you have any idea how hard it is to keep a set screw on a flat head screwdriver?  Magnetizing the screwdriver did not help.  It almost seems as though the set screw is not steel.  After I lost that one, the next one fit a 1/16" Allan head wrench.

4. You are supposed to countersink tapped holes but my smallest countersink is too large to fit in the available space.  I obviously need to buy a midget (is that word still allowed?) countersink.  Still, it went in (perhaps because my starter hole was with a center drill which leaves a small countersink) and screwed it down onto the screw quite solidly.

It is not going anywhere on that screw.

It turns out that the collar on the 5/8" diameter thumb nut is quite a bit smaller and drilling an tapping a 6-32 hole is impractical.  Let's try the simple but inelegant solution: SuperGlue!  Or look for a 4-40 set screw.  Let that dry an hour or so and see if it passes the application test.