Review on BINOTA Concrete Shank Cement Brick by Desmin Dickerson

Considering that 'big brands' charge more for a hole saw, this set is a good investment. They worked well enough for a few holes, despite the age-old hardened concrete and hollow tiles. Cons: 1. The guide jet adjustment screws are plain M6x1 hex head screws, loose and prone to falling out. I replaced them with real M6x1 set screws and teflon tape. You could still withdraw every time.2. Be sure to grease the threads on the mandrels as they are not easy to remove from the hole saws. I needed two large pipe wrenches to separate them.3. The SDS-max spike failed within a week. I used a Hilti TE-60-ATC and was able to cut it as shown in the photos. Very disappointing as SDS plus RP hammers don't have the power to drive 80mm and 100mm bits. If anyone knows how to get a replacement SDS-max mandrel that would be great.