PHITUODA 12pcs 1/4inch/ 6mm Diamond Drill Bit Tile Hole Saw Hollow Core Drill Bit for Ceramic, Porcelain Tile, Glass, Marble, Granite, Quartz

Funcionan bien. Hay que utilizarlas con mucha lubricación. Aun así practicamente son para una o dos ocaciones maximo.

Would give these a -100 star review if I could. Doesn’t matter if you use water, you will get 1 hole per bit. The worst things I have ever purchased!

I have tested 3 different kinds of drills on porcelain and glass. These are the best I have found so far. These have the least breakout and the 2 I have tested are still cutting. (35 holes so far). I have been drilling under water on a drill press. Of course, you have to use minimal pressure especially near the end of the cut as with any diamond drill.

I used these to drill holes in porcelain tile. Don’t go too fast, use water frequently, and apply moderate pressure. I bent a bit with too much pressure and got only one hole from it. The other bits were good for two or three holes with some patience. No way they’d last six holes in porcelain tile, but at this price I didn’t mind replacing the bit after 2-3 holes.

The cut good through a 1/2” porcelain BUT they are good for only 1 cut per hole saw even with constant water flow over the bit as I did… at least you get 5 per order