I returned to Tucson for the last week of February and the first week of March. First I went to Home Depot and bought a $90 percussion drill and started to make holes to split a big rock. It took a lot of time and patience, but eventually I had six 1/2 inch holes about 3 inches deep. I inserted the feathers and plugs and started tapping, lightly and evenly, and patiently, until, with no warning, no visible or audible cracking, the stone simply fell in half. However, when I tried to do more splitting this way, no amount of time or patience yielded a deep enough hole. I first thought the stone was too hard and was killing the drill bits, and I wasted a lot of money on extra bits, but evntually concluded that my drill was fine for cinder blocks and bricks, but for igneous stone I would need a more monstrous drill in the $300 price range. But first, I decided to see what I could do with 7 inch diamond-tipped circular saw blades.