Disappointing performance, especially considering you're paying a premium dollar for these crowns. These are general purpose, construction/industrial quality hole saws for cutting light weight masonry, tile and WOOD. While drilling a 2 x 12 beam I hit a cheap soft metal Chinese nail and 2 of the 3 carbide teeth broke. I would expect this from no-brand hole saws designed for homeowners, not made for construction and priced well under Bosch. Bosch is said to be a top of the line product so again very disappointing.