Stadea Granite Core Bit Diamond Hole Saw for Granite Marble Concrete Stone Masonry Cutting - 1 5/8" (Pack of Four)

First these are cheap in cost and quickly available through Amazon. I bought one and it worked beautifully. Its function was on par with other premium ones costing $70+ each. I needed to drill 260 holes in glazed brick and mortar. So one would not suffice. After the great results with the first one I bought 5 more. Two of them would not even punch through the surface. I have yet to try the other remaining 2. The diamonds were not bound to the bottom of the segments. So i tried another and it too had few diamonds but did try to cut slightly, I changed to another and viola just like the first one, it cut like butter. So the 4th one worked as good as the original. So I figure you need to buy 3 to get one good one. In the photos you can see where i tracked the efficiency of the tool. At the time of the photo i had cut 58 holes and it was still going strong. I am 170 holes into the project with only 2 bits. Regarding the photos the one beside it would not do anything and was new out of the box.Summary, If you get a good one it works great. If you get a bad one it is crap. Good luck.

Drilled through this Millstone in about 15 minutes. I believe it maybe granite. The bit itself is too short so I bought the harbor to extend drill depth. But it turns out the larger collar at the top of the bit limited penetration depth anyway. Also bought the 3/4" bit & drilled six holes in same granite, 3" deep. Always used water trickle for lube & cooling. Went about 1" depth per 3-5 mins (rock density varied) with my full weight. Hard work! No sign of wear. (Tungston carbide Bosch bit from bigbox store hardly scratched the granite).

Sturdy and precise. In the past I have bought similar bits from different companies only to have them lose a tooth on the first hole. I attach this bit to a cordless grinder for precise medium-speed cuts through granite (I use some water to keep the dust down), and have seen great results so far.

did the job of Dry cutting 21 holes in Granite ,would buy again !!!

Great

Worked well, better than hole saws I got at Home Depot which became useless pretty quick.

I used this bit to drill a 1-3/8" hole in my foundation (8" thick). Worked great. I took it slow, drilling for ~30 seconds, spraying the bit and my hole with water to clear out debris and to cool things off. While the bit still has plenty of life left, I would most certainly buy again if needed.

Went slow but through in a couple of minutes, works great