From my local scrapyard guru, a handy way to cut accurate holes with an oxy-acetylene torch
Whenever you run into a snag on a project, it's a pretty safe bet that somewhere there is a grizzled old man who's solved it many years before you and will be happy to tell you it. That's why I never miss the chance to chat up the old guys working at or just hanging around lumber yards, machine shops and scrapyards. I always walk away smarter.
One recent example: While helping PopSci's John Carnett with his Green Dream house, we had to make a number of bolt holes in thick structural steel. (I would have preferred that the beams had come from the steel yard properly cut and drilled, but sometimes things don't work out as we'd like.) The drill just wasn't cutting it, so I turned to the oxy-acetylene cutting torch. It would easily pierce the thick steel, but I wasn't sure it'd cut clean holes. Then I remembered a great trick for burning accurate holes that I learned from an old-timer at the structural steel yard.