Thread: You know that sound???

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Originally Posted by TerpnGator

Actually John, tools marketed and sold as "thread chasers" ARE JUST REGULAR TAPS. Most, if not all, are cheap, normal carbon steel and most with only 2 flutes. In fact, the only advantage to using a carbon steel tap is if it does break it is much easier to drill out.

Nobody makes an "undersized" tap to use as a thread chaser. This machinist friend of mine actually had a tool that he made to chase threads in a project that he worked on. It was no more than a hardened steel bolt that had a sharp troth cut into the length of the threads.

If you want to clean up your threads, lube your tap well and slowly run it in. A 3/8 tap WON'T cut new threads unless you cross thread it in. It will cut 3/8" threads just like new.

I emailed a friend who has been a machinist most of his life. His comment was:

"Interesting. I had never heard of a tap called a thread chaser. Used what was available starting-bottoming. I have also taken a bolt and ground a slot with a slight "cutting" edge to clean the threads."