I think one of the other problems if the flexibility of the props themselves. APC does flex, but when the reamer (or bit) goes to work it is firm enough to be bored correctly. When you use a Master Air screw it likes to flex or get pushed out of the way. When you remove the reamer it is still tighter than expected. I bought a $5.00 HobbytownUSA one (cheep I hear) and have had no problem in about 50 or so props. The composition of the props has a great deal to do with it. As for using a drill or drill press I go for the press of course and yes a hard clamp with low speed (very low). Even a slow turning prop can have enough force left in it to take finger tips off. How thick of a glove is required? I can't answer that, and just because it has never happened doesn't mean that it won't. An ER run for stitches can run well over $100.00, and a prop hand reamer as cheep as 5 bucks....makes the choice easy, at least on this camp.

Either way be safe.

Lefty