10 Pcs Diamond Hole Saw Set with Diamond Drill Bit Guide Included 1/4, 3/8, 1/2, 3/4, 1, 1-1/4, 1-3/8, 1-1/2, 1-3/4, and 2 inches Diamond Drill Bits for Ceramic, Porcelain, Tile, Glass Drill Bit Set

I purchased in January 2021 for $44. I actually needed 3 of the sizes that this 1 kit came with. I went to several tile shops, supply houses and looked online and I found that price of just ONE of their bits was more than this set. I figured worst case scenario, I would burn them up, finish the job and pitch them in the trash!2 years later and I have absolutely punished these bits and they haven’t slowed down a bit!I’ve used them on porcelain and ceramic tile, 2 granite countertops and the ultimate torture test was drilling through 3/4 granite tiles. I needed 4 inch round holes that kept cracking when trying to use a grinder. I decided to use these bits to drill multiple holes to make the 4” hole and it worked great!You can use the foam backing pad that holds the bits to CENTER it since the bit itself doesn’t have a centering bit. Get the hole started by holding the foam piece with one hand, fill it with water to keep the bit cool, then start the bit slowly with the other hand. I used a Dewalt battery drill and they worked great. I do keep them cool with water and low RPM’s while using them. I’ve even let a friend borrow them and they are still good.The ONLY CON: They are not deep enough to go all the way through a granite countertop. Bit is too shallow. So you can either start the top and go as far as possible then tap it out with a hammer. Or start the top and go as deep as possible then switch and approach from the bottom if you need to.For all tile including porcelain, just take your time and keep the bit wet and cool and they work and will last! Work great on tile backer board also!Definitely recommend them though!