These hole saws also work on very hard porcelain stoneware. When my kit arrived the 1 1/2" piece was missing, but an email to Drilax quickly resolved the issue. This is DIY quality (no professional tools) but will be fine for the average homeowner. I drilled several holes of each size with plenty of cooling/flushing water, based on my experience I expect to be able to get 10-15 good holes out of each hole before they go hopelessly dull.bucks.