Review on Diamond Ceramics Porcelain Ceramic Marble by Carlos Phillips

I was skeptical about these cheap beats because of all the negative reviews but they did a wonderful job. As long as there is a steady stream of water flowing through the hole, you should be fine. I hung a bag of water over where I was drilling and punched a hole in the bag so the drops would fall directly onto the tip of the drill. I drilled 4 holes in incredibly hard 3/8" porcelain and noticed the drill was starting to dull, so I replaced it with a new one and drilled the 2 holes you see in the attached photos. Keep it wet and use medium speed and pressure on the drill and it will work great. This pack of 10 will give you at least 40 clean holes. These bits worked much better than the Bosch carbide bits I also bought.