I was looking for a fitting for my square ended tap, so i don't have to cut 3 grooves above the square in order to prevent it from sliding. I can't seem to find what I'm looking for. I was hoping to find a hex shank with a female square hole. Do these exist? If this isn't what you guys use, can you tell me what you guys do to prevent the tap from turning in the chuck? I tried tightening it down with all my might but it still turns when chucked against the round shank above the square.