david weaver
Yes, I think cutting fluids are good except I'm using the water as a cheat to indicate heat, and it's gone when I leave, so I don't have to clean it up.

Cutting fluids, etc, may prevent more of the heat in the first place and extend the life of the bit, but bit life isn't much of a problem as i can freehand sharpen the bits, and the big bits like 3/8" are very easy to freehand vs. the smaller ones.

oil based cutting fluids (i've never looked) or even water based, whatever they may be, probably come in all kinds of smoke points, but I did find out with Wd40 as a cheap substitute for one, once it's smoking, i'm pretty close to being in trouble with hardening on these irons.

Water is good in this case because the penalty for this stuff hardening (you can't remove the hardness by just bluing it to get to spring temper - it only loses a couple of points between 400 and 800F) is much greater than the time wasted drilling.

Not that I would mind having a mill and a constant trickle of fluid, but I'd hate to learn to use anything like that at this point.