When to use forming tap

[jeffrey001]

I would like to know when it is best to use ordinary tap or forming tap.

What condition should be considered to use a forming tap, is it the futur of tapping?

Do they provide better result when you need 2A tapped hole.

At the end, is the result always better with forming tap.


Thanks for your time.


Jeff

[txcncman]

As almost all machining, this does not have one simple answer that covers every situation.

Forming taps can be preferred when tapping blind holes because essentially there are no chips.

Forming taps can also be preferred when tapping "softer" metals because the forming (actually extruding) action somewhat work hardens the metal making stronger threads.

Forming taps apply more cutting forces to the material and to the tool, which can lead to tool breakage. Forming taps generally take more horsepower because of this.

Cutting taps (what you call ordinary taps) make chips. Chips can bind the tap causing breakage.

Forming taps make more consistent threads than cutting taps.

[fizzissist]

Here's a little overview for you....as noted, forming torque is higher, but I have NEVER had a problem with that, in copper, brass, aluminum, or stainless steel.

Threads Will Roll

I love forming taps whenever I can use them. They are more expensive, but the biggest issue is controlling the drill diameter. It is critical. Little variations in hole diameter translate into Big variations in the thread height.

I've tapped hundreds of class 3 0-80 blind threads in 304 SS with a forming tap.
One thing I love is the increased strength of the threads and the beautiful finish.

[jeffrey001]

Thanks for those replies guys, really appreciated.

Is it always accepted by the industry, does the thread have the same specification, like if I use a thread gauge to inspect a hole tapped with a forming tap, say a 1\4-20 2A, will it be accepted by all your clients.


Again, thanks a lot.


Jeff

[john_100]

Hi Jeff


a "friction drill" and a thread forming tap ( or thread forming screws eg taptite ) are used to produce a strong thread in thin metal

John

[txcncman]

@Jeff - Yes. Unless specified differently on the print, threads should be considered to be to industry standards and you would use the same thread gage for checking.