Cutting dry for ever. I found this to cut faster for me. Hole saw life in my experience has been directly related to how much heat is put into the hole saw. The most harm to the saw (IMO) depends on how much material is rubbing on the inside of the saw. I will cut half way, stop, and remove the piece, then plunge again for the rest. This also reduces the chance of the piece jamming against something near the finish. When you jam against something it can bend the saw out of round or off center. Slightly bent hole saws are trash to me.
Edit>>> Tooth per inch is important for hole saws, sawsall, bandsaw, etc... I believe the rule of thumb is no less than two teeth making contact at all times. This is more relevant to thin material. Not enough teeth making contact will cause chattering, witch will damage the teeth.
Last edited by ScooteK; 02-08-2017 at 08:47 AM.