Review on Diamond Drill Masonry Drilling Tools: Unparalleled Precision and Performance by Leo Fairchild

I drilled 5 holes in a concrete block with an 85mm hole saw. It is important to follow the instructions for starting the hole and the "wobble" technique. Additionally, light wetting with water while drilling is also important to cool the bit and remove debris. The bit shows little wear but I think I can drill between 8 and 16 holes with this bit before it gets too boring. I want it to be 1/4 inch deeper as I couldn't break through the standard concrete block all the way, there was about 1mm left, maybe less. A light tap of the hammer finished the hole without knocking out the inside of the block. Of course, it's not a replacement for a core drill if you're a pro or do it regularly, but if you're a DIYer and just need to drill a few holes in hollow blocks, this is a great option.