The drill I bought together with the Bosch Rotary Hammer GBH 2-20 D, after I tried to drill with a percussion drill holes in concrete and with three holes two drills have sacrificed. With the hammer and these drills drilling holes is a real pleasure. However, without exception, all run drills round. Depending on the length of the drill the game is 1mm in well. No it's not the hammer. I have tested it with drills from another set. The drilled holes correspond to the respective size of the drill, but I expect in drills that mark an appropriate quality including an accurate concentricity belongs. Therefore, the drill back and I'm going to order me another set.
