drilled through a concrete foundation. It started well, slowly but surely. After about 1.5 hours with the Bosch hammer drill, I only went about 4 inches before half of the carbide tips broke completely and the rest wore out. I used some water to cool the bit but it seemed to cut faster when the bit was dry. The pilot bit was fine but not very aggressive like a Bosch bit. The threaded pin/bolt does not remain in place despite turning. As soon as the main well started, I gave up the pilot. Gets three stars because the price is right / you get what you pay for. This can work well on block but is not recommended for solid concrete in my opinion.