Compared to the old way of using a separate drill and tap, it just sucks! Hard and long! This taps threads with a little more work than drilling a hole! Make sure to slow down when he starts threading. Reverse part of sales when they tie. A bit of cutting oil won't hurt, but there's no need to hammer on the aluminum. The force of the punch tends to push the tap against the hole. Too bad I didn't find them years ago - I will never use a regular faucet in any of these 5 sizes again! (And will probably look for more if I need other sizes.) They're better than sliced bread, popcorn butter, and twine. Things that need string concatenation.