Originally Posted by Shoalwaters
Scary is right on the money. An electric drill powerful enough to drive a 5" hole saw is also powerful enough to do serious injury if the cutter jams in the hole. The weakest link in the hull/cutter/drill/ person chain is your wrists. If you can't get a Hole-Hog/Hawg, make sure you have a really good grip on the drill - one hand on the pistol-grip and the other on the back of the motor casing.
Absolute truth there. The worst injury in my career was drilling a 3 5/8" hole through a steel stud top plate with a hole saw in a 1/2" drill. My personal choice for hole saws over 3" is my 500 rpm Milwaukee right angle drill with 1/2" chuck. Gives plenty of leverage and control.