Comments by "Julian Petkov" (@julianpetkov8320) on "Best Hole Saw Brand? DeWalt vs Milwaukee vs Irwin, Bosch, Lenox, Diablo, Bosch, MK Morse" video.

@ProjectFarm They all suck at it, but it is a very difficult cut without coolant. Cubic boron nitride would have handled the armor plate easy. Try with lighter speed and feed.
9
@pflaffik I have trick for the home shop for tempered steels. I touch the hole to be with a stick welder for about two seconds. Carbon electrodes are best for the purpose. They are made for cutting. It will soften the spot. Like you said, there is no point wasting carbide on hobby machines.
6
@gamerdew641 You don't need to use a coolant on wood. If you want a super clean cut, you need screw a piece of wood on the other side of the cut, to avoid chipped edge.
2