Spiral tap is a tool for machining threads. It is named because of its spiral flute. Spiral flute taps have the advantages of long life, high efficiency, low cost, good cooling and lubrication conditions, smooth cutting, easy insertion, and low torque. Spiral flute taps are the most commonly used type of taps. Different spiral angles are used according to different working conditions. The common ones are 15° and 42° right-handed. Generally speaking, the larger the helix angle, the better the chip removal performance. Suitable for blind hole processing.