Only use tapping bits, never a wood boring or metal boring one from a hardware store. They ARE different and they cut cleaner holes. I use 2 speed cordless drills and only use high speed. Be careful not to wobble the drill. Then tap in with a light tap. I use 7" lineman's pliers, using the flat side to hammer, usually 3-4 gentle taps, then the sound changes, don't tap anymore. You can also use a light wt hammer like a tack hammer, or a tapping hammer with a nylon head.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.