Hey,
Your best bet is to use one of the adjustable hole cutters, I have never
seen a hole saw that actually cut the diameter that was written on the side.
I guess the wobble factor , etc. If you use a 2 1/4" hole saw you may well
end up with a 2 1/2 " hole depending on thickness of material.

Patrick
student SPL
aircraft structural mech


wrote in message
oups.com...
I need to cut a panel to mount one 3.125" and one 2.25" What size hole
saws do I use? Do I use smaller sizes, say 2.125" for 2.25" and 3" for
3.125"? Thanks.