RoyJ wrote in
:

Hope someone can settle an argument: The part is a 1" long x 3/8" OD x
3/16" ID brass bushing that needs a 6-32 set screw. Tap drill goes all
the way through both walls for convenience. Hand tap with straight flute
tapered tap and 'T' handle. Quick prototype level part, only making 2
of them, precision not required.

Questions: tap dry or use what lubricant? Backup the usual 1/3 turn to
break the chip necessary on this part?

Do yourself a favor and go buy 2-flute gun taps in all the smaller sizes you
use, and 3-flute gun taps for the larger sizes. They throw the chips in front
of the tap, which means you'll never have to back up in any material unless
it's a blind hole, and then only to empty the chips when you're done. Tap
brass dry, aluminum with kerosene or d-limonene (orange oil), and steel with
Rapid Tap. Once you try gun taps, you'll wonder how they still sell the
standard 4-flute taps.