I inherited an Ace Super Hex tap and die set back in 1978 and have used the taps far more than the dies in the years since. Recently, however, I was trying to use the 1/2-20 hex die on an unthreaded rod and was unsuccessful. I had turned the OD down to 0.495” (major dia. minus 10% of the thread pitch) and added a substantial lead-in chamfer and the material is ordinary hot rolled steel. Research on the Internet leads me to believe ALL hex dies are actually rethreading dies and the round variety are for cutting new threads. It’s the first time I’ve ever heard of this so I have to ask: is this true?
4thTool
4thTool