Thread: You know that sound???

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Originally Posted by pepi

It take a different bit to clean up threads, taps are for cutting not cleaning. Here is the bit for chasing the threads. I know it is to late for future reference it is a good thing to know.

ARP 911-0002, ARP Thread Cleaning Chasers | ARP
"Note: These are strictly cleaning taps and are NOT designed to cut thread."

Glad all turned out well and lucky it broke off close to the surface...

OK--I got hammered on another site about using a TAP as opposed to a THREAD CHASER. I have heard the term THREAD CHASER" but never seen a tap labeled as such. Therefore, I consulted with a friend of mine that is a retired machinist for NASA (now is a consultant/trainer for large industrial machine Co.) and over the course of an afternoon got a, hands on, education on taps and dies.

In the world of machinist, where taps and dies are a daily tool, THREAD CHASERS are a joke. What I mean is this. There are no "quality manufactures", Morse, Greenfield, Yamawa, Emuge or OSG that make anything called a thread chaser or cleaner. The ones from APR are cheap taps, not HSS, same as you would buy from HF. The ONLY advantage in using a tap such as this is if it does break you can drill it out as they are NOT HSS (high speed steel) These are the taps that I, normally, use to clean up threads because they are CHEAP, meaning they are not as aggressive as quality HSS taps.

There are other types of taps called roll taps or forming taps. These taps, which can't be used in every metal type, actually FORMS the threads in the metal as opposed to cutting them.

So, don't be fooled by deceptive advertising. If you want taps to CLEAN up a thread, buy a set of HF.

Interesting discussion... I've always just used cutting taps for chasing threads too

Anybody ever taken the time to look and measure a "chasing" tap vs. a "cutting" tap? I'd assume the chasing taps are merely a bit undersize?
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Originally Posted by lakeroadster

Interesting discussion... I've always just used cutting taps for chasing threads too

Anybody ever taken the time to look and measure a "chasing" tap vs. a "cutting" tap? I'd assume the chasing taps are merely a bit undersize?
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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.

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."