Review on LOT Pcs Diamond Hole Drill Bits - Cutting Tools by Jack Bhowmik

Bought these to drill two holes in a granite countertop. The beats work well. If you keep the bits wet as directed on the packaging, they will cut quickly and cleanly. The only downside to these bits is that they don't have a pilot drill to start a pilot hole to hold the bits in place so they can slip and scratch the surface. I just attached four pieces of wood to the top, leaving a hole big enough for the drill to not move. . However, after drilling individual holes, the cutting edge looked fine. If you run your bits dry, you're likely shortening their lifespan significantly. Although I only needed two bits, I would buy this set again as the price for the entire set was lower than the price I got if someone just drilled one of the holes.