Drilling brittle materials need to drill pressed on the material with limited power. Regulate such power may gradually, using a smooth change in weight of a liquid or bulk material. That at the moment of touching the drill to the details of their relative rate was the lowest, the initial distance between them is to be too low as possible. For the least possible advantage of liquid at the end of file should be as slow as possible, which can be realized by using something like the dropper with a shutoff tap.