L1 thru H6 Taps

[Wamsutta]

I found this Practical Machinist thread.

Correct me if I'm wrong:

If I wanted to chase some threads and a thread chasing tap was not available, I would want to use an L1 tap; correct?

An L1 tap would be smaller in diameter than the other extreme which is an H6 tap.

If I was to tap a fresh hole with an L1 tap, that finished threaded hole would be tighter than a mother effer.

But if I wanted to clean some threads without the risk of enlarging the threaded hole and making it a sloppy fit with the threaded fastener, an L1 tap would be ideal. Let me know if I'm correct or way off base. I need to get to the bottom of this.

 

[Tiny Jackson]

I found this Practical Machinist thread.

Correct me if I'm wrong:

If I wanted to chase some threads and a thread chasing tap was not available, I would want to use an L1 tap; correct?

An L1 tap would be smaller in diameter than the other extreme which is an H6 tap.

If I was to tap a fresh hole with an L1 tap, that finished threaded hole would be tighter than a mother effer.

But if I wanted to clean some threads without the risk of enlarging the threaded hole and making it a sloppy fit with the threaded fastener, an L1 tap would be ideal. Let me know if I'm correct or way off base. I need to get to the bottom of this.

Yes but even an L1 will cut threads which can mess up your existing threads. be real careful especially if chasing in aluminum.

If chasers are not available, you can make them by grinding two flutes into a bolt of the corrrect thread pitch.

 

[Wamsutta]

Yes but even an L1 will cut threads which can mess up your existing threads. be real careful especially if chasing in aluminum.

If chasers are not available, you can make them by grinding two flutes into a bolt of the corrrect thread pitch.

So am I on the right track? L1 will cut less than H6 ?

Like that other guy said in his thread, sometimes thread chasers aren't available for small screws like M4 and 10-32.

 

[Donnie O]

It all boils down to the use of a part. If you mess it up put in a helicoil.