Review on 9.5" Diamond Dry Core Bit For Brick And Block With SDS Plus Pilot Bit Adapter, 5/8"-11 Arbor And 9.5" Drilling Depth - Perfect For Concrete Drilling by Ray Gist

Needed to drill 3 holes through concrete block wall for mini split installation. One of the holes turned out to be solid. Drill worked much better than I expected, being a dry bit. I suggest forgetting about the pilot bit, and saving it for other uses. The bit is too long to center properly, and will not guide the blade to the center anyway. Not the fault of the hole saw, it is just long. Instead, I drilled a 2.5 inch hole in a 2x4, then mounted it on the wall with Tapcons, and used it as a guide to start the diamond hole saw. Once it gets started, it eats up the concrete! Be careful if you are using a powerful drill, it will bind up and twist your wrist, or in my case spin the drill motor and punch you in the nose! (My fault, not the product.) Worth every penny even if I never drill another hole with it, but I certainly can.