Review on FACHLICH Diamond Granite Concrete Drilling by Jonathan Olson

It only took a ceramic tile to blunt and round the tip of this ¼-inch drill bit. I used a wet sponge to keep it cool. It seems that first bit of two is almost useless now as it doesn't even make a second hole in the porcelain. I have a $90 bit that I've used on all kinds of rock and tile probably 50 times. the comparatively more expensive bit has a much better value.