転造タップでの加工で、ねじ山の山頂が形状不良　その対策は？ | オーエスジー

forming tap is always cracked at the top of the thread pile during processing.

If the shape of the part is defective, the pilot hole diameter before forming tap machining is too large and the rise is insufficient.

Alternatively, it is possible that the pilot hole diameter is too small and is too raised (overrolled).

Alternatively, depending on the type of tap, there is also a type that cuts off the top of the thread after the rolling process.

In addition, there is also a type that suppresses cracks at the top of the mountain during the rolling process, which is often requested for small diameter precision parts. (IT-NRT)