EMUGE Punch Tap

Faster tapping due to shorter tool path


The EMUGE Punch Tap – technology, also called helical cold-forming of threads, constitutes the fourth method for the production of internal threads besides tapping, cold-forming of threads and thread milling. This patented method was developed in cooperation between Audi AG and EMUGE-FRANKEN and presented for the first time to the public in 2014.

Thanks to entirely new kinematics with a significantly shorter tool path, the Punch Tap allows for time savings of up to 75% compared to conventional cold-forming of taps.

To enable this movement path, the tool does not have a continuous thread profile on the circumference, but features two rows of flutes. These flutes are off-set by 180° and extend in a helical curve all the way down to the usable application depth.


The basic movement path of this process consists of 3 steps described in the following:

Step 1: Plunge

Upon entering the predrilled hole, the first tooth (broaching tooth) of each flute produces a groove. The helical infeed into the pre-drilled tap hole moves the Punch Tap to the application depth. This first process step does not yet produce a thread.

Step 2: Thread-forming

Once the Punch Tap has reached its depth of application, the cold-forming of thread starts. This is achieved with a synchronous movement of feed and rotation. The thread is produced with a half left-turn in the pitch. Each tooth of the Punch Tap produces half a thread (approx. 180°).

Step 3: Retraction

After the threads have been formed, the Punch Tap is retracted in a helical movement from the bore hole using the path of the produced grooves.