I finally just tried out this bit on my 2" thick granite slab using a jig to keep it from walking and using a constant a water trickle. It was the hardest hole I have ever drilled it took me over and hour to barely do one hole 2 1/2 " inches deep. My 7amp corded drill went up in smoke and the bit is completely smooth now no more diamonds can be seen or felt. It refuses to even start the second hole and I have 14 holes to drill. I spent a lot of time researching the appropriate bit and asked lots of questions in your chat before I decided to purchase. Saying I am disappointing and honestly feel ripped off is an understatement.