IFR and Air Bleed sizes?

I use brass set screws from Fastenal for IFR's and TSR's, bleeds I usually buy 10 packs of 24's and drill them. I made a fixture to drill IFR's and TSR's out of a piece of 1/4" aluminum by not tapping the threads all the way through. This way the set screw bottoms out in the threads so I can drill them without them running out the bottom.