A small tap can contain so much information. . .

Tip Spiral Groove
It is beneficial for chip removal to be more durable and suitable for through holes compared with straight grooves. The disadvantage is that the invalid wire at the tip is too long.

Simple comparison relationship between straight flute, spiral flute and apex spiral flute taps:

Spiral fluted tap
Spiral fluted taps are mainly used for threading blind holes. When machining workpiece materials with high hardness and strength, taps with smaller helix angle can be used to improve the structural strength.

For machining 400 series stainless steel (15° helix angle)

For machining 300 series stainless steel (helix angle is 41°) Fig. 3 Spiral flute tap

Spiral vs. Apex Spiral
The spiral shape is suitable for blind holes, and the iron filings are discharged to the outside of the hole. The apex is helical, and the chips are removed downwards. 3d machining

Intuitive comparison of straight and helical shapes

Tapping of special workpiece materials
The machinability of the workpiece material is the key to the difficulty of tapping. According to the properties of the material, it is very important to change the geometry of the cutting part of the tap, especially its rake angle and the degree of concave in front of the concave amount. 4 axis cnc machining

Rake angle and sag
Machining of high-strength workpiece materials
For high-strength workpiece materials, taps typically have less rake angle and undercut, increasing cutting edge strength. Long-chipping materials require larger rake angles and undercuts for chip curling and chip breaking. Machining harder workpiece materials requires larger relief angles to reduce friction and adequately cool the cutting edge.
Machining materials with different degrees of softness and hardness
For materials with high machining hardness and strength, the tap should choose an eccentric relief angle from the cutting edge.
For example, when machining stainless steel materials, a helical groove with a small rotation angle is used to cope with the hard and sticky processing characteristics of stainless steel, so as to facilitate long-lasting cutting and chip removal of blind hole tapping.

Common problems in the process of tap tapping

There are many reasons for tap breakage: machine tools, fixtures, workpieces, processes, chucks, tools, etc. are all possible, and the real reason may never be found on paper. All of the above problems require operators to make judgments or feedback to technicians.