david weaver
A second or two of drilling each hole and then just do the same thing on the holes in order, like repeatedly walking up a ladder until the holes are through.

Though water isn't the right thing to use, I like to dribble it into the drilled holes because it cools the metal and acts as a canary when drilling. It steams off quickly, then you move to the next hole.

For cutting, if you keep it moving, it cuts fine. I'm sure an assistant dribbling water or fluid on it could also keep the temp down, but that's not something I want to figure out. If you stop to regrip while sawing, it'll harden wherever you stop, but not deep - a bimetal blade will get through it within a second or two and you're on your way again. I don't notice much change in sharpness with the blade (one of the type marketed by dewalt for about $7 each in packs of 3).

The whole process would be scoffed at by a real metalworker, but it yields plane irons pretty quickly (relatively) and at low expense.