As usual for me, a day late and a dollar short
........ My two cents worth, or is it a nickle now?
First off, a Nr 10 machine screw is 0.190" (060+(.013x10))
Next, a 3/16" stove bolt is 0.1875" (2-1/2 thou smaller)
Threads for 32TPI are 1/32 (0.03125") less than that to tap.
That yeilds 0.15875 as the optimum drill size. Use the closest larger drill for tapping. I don't have handy a chart, but the closest drill may well be metric. Who knows?
I could lecture on aluminium as being tenaceous, but I won't. I do remember breaking more taps in it than in steel. Panel steel was gauge 11, call it 2mm. Aluminium was 3mm, m/l. In my experience, 10-24 was a much more usable size in aluminium. Hanging electrical components
....... Of course, troubleshooters usually had some 10-24s in their pockets. Only the electronics guys kept extra 10-32s.
Bill Hudson