Eliminate the Speed and Feed Variable

Pitch cam in a Top Cut bent shank tapping machine.

The primary gain is the ability to run at much higher speeds and still maintain the best thread quality. The tap life can still be as good as in machines that run at half the speed.

Streicher Maschinenbau GmbH has been manufacturing tapping machines for almost 80 years. Nearly 2000 machines have been produced by Streicher and are distributed in more than 70 countries.
Over the years, there has been a variety of different tapping machines, both bent shank (over tapping) and reversing style. Today, the primary nut tapping machines we are making is a series of two spindle bent shank tappers, the Top Cut, and a series of single spindle reversing tappers, the Varimac. The number one thing these machines have in common is that there is a mechanically controlled relationship between spindle speed and advance stroke speed. The Top Cut machine uses two plate cams to control the advancing of the carriages. The Varimac uses a lead thread driven by a servomotor to control the advance and return of the tapping spindle.
Eliminating the speed and feed variable in tapping machines has proven advantages. The primary gain is the ability to run at much higher speeds and still maintain the best thread quality. The tap life can still be as good as in machines that run at half the speed.

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