Ok, so here's a weird problem. I am trying to make a 1/4 npt fitting with two pieces of brass pipe. The tap says: Vermont 1/4 NPT 18 HSGG M21 The die says: 1/4 NPT Baystate -5 So I threaded the pieces of pipe, expecting them to fit together nicely... and they didn't - far from it. I found that they were screwing in at an angle, and stopping after a short distance. Needless to say I'm mystified by this. I've tried threading several pieces, being careful to make nice straight threads, and still this problem remains. I suspect it must have something to do with that "-5" on the die, but I haven't been able to find any references explaining what it means. Please help!