Review on Diamond Porcelain Hole Saw Extractor by Evan Hernandez

They worked perfectly and didn't cost that much for a set of 15. I was able to drill 12 holes in large porcelain flower pots in about 45 minutes using a ½ inch deep portable drill bit with a ½ inch drill bit. I started slowly at an angle of about 30 degrees at a speed of about 10-20 rpm, gradually approaching vertical. After the tack I was able to accelerate to around 200-300 rpm but kept the cut wet and paused every 30-45 seconds to keep the bit cool. I believe the wobble that others complain about is because it doesn't slowly move at an angle until a full circle has been engraved. It took me a few holes to get the hang of it, but after that it was pretty quick. Another tip: when you're almost done, slow down again to get a clean cut on the other side.