How to select a tap?

Taps as a common tool for processing internal threads, according to the shape can be divided into spiral slot tap, taper, straight slot tap and pipe thread tap, etc., according to the use of the environment can be divided into manual tap and machine tap, according to the specifications can be divided into metric, American, and British tap, etc.. Taps are also the mainstream processing tools used in tapping. Then how to choose the tap? Today I'd like to share with you a tap selection guide to help you choose the right tap for your application.

1、Straight  tap: Used in the processing of through holes and blind holes, the iron chips exist in the tap groove, the quality of the processed threads is not high, more commonly used in the processing of short-chip materials, such as gray cast iron.

2、Spiral tap: used for blind hole processing with the hole depth less than or equal to 3D, the chips are discharged along the spiral groove, and the quality of the thread surface is high.

10~20° spiral angle tap can process the thread depth less than or equal to 2D.

28 to 40° helical angle taps for thread depths up to and including 3D.

A 50° helical tap can be used for thread depths up to or equal to 3.5 D (4 D in special cases).

In some cases (hard materials, large pitch, etc.), spiral slotted taps are used for through-hole processing in order to obtain better tip strength.

3、Straight Pointed tap: usually can only be used for through hole, L/D ratio up to 3D ~ 3.5D, iron chips discharged downward, small cutting torque, high quality of the processed thread surface, also known as taper angle tap or apex tap.