Used immediately upon receipt to drill holes in hard porcelain stoneware. The chisel worked well and was used with good water lubrication and not too much pressure. The chisel worked well, the first half of the hole dulled very quickly, in the end I had to move it a bit and the hole was done. The second hole was hard work, almost impossible to finish. On the third, I have to use the second bit with the same results. On the upside, they could make holes, but at great cost. If you need to drill more than a few holes in hard tile, look elsewhere.