Colour ring machine tap

Colour ring machine tap (DIN 371 / 376)

In today’s article we would like to give you all the important information about machine taps with colour rings. There is a large number of different colour rings on the market. Blue ring, red ring, yellow ring, green ring, white ring and even black ring. What do these colored rings mean on machine taps? What exactly do they mean? What is the difference to machine taps without a coloured ring?


Colour ring machine tap: blue ring, red ring, yellow ring and white ring machine tap


Machine taps that have a coloured ring on the tap shank are called coloured machine taps or also coloured ring machine taps. Different metallic materials, such as stainless steels, heat-treated steels or grey cast iron can be machined with coloured rings.

What do the coloured rings on machine taps mean?

The assignment of the coloured rings varies from manufacturer to manufacturer. The colour rings on high-performance machine taps help manufacturers to better assign the taps to the individual material groups. The colour coding is left to the manufacturers

What are material groups?

Materials have different properties. Materials that have similar characteristics are grouped together in material groups. These material groups are defined according to the ISO standard (DIN 371 / 376).

For a better allocation of the taps to the individual material groups, the high-performance machine taps are marked with colour rings, each of which can be allocated to a material group. We have decided on the system shown below.

Colour ring machine taps and material groups

The rake angle determines the chip flow of the material and thus the cutting performance of the tap. It must therefore be adapted to the mechanical properties of the material to be machined. For this reason, the individual materials are combined into material groups, each of which has the same or similar mechanical properties. Well machinable steels with a tensile strength in the range 400-900 n/mm2 can be machined with the machine taps of the standard program. Special adaptations of the cutting geometry for special operating conditions are possible in individual cases.

You will find colour ring machine taps in our GSR-Shop

Click here for our new digital catalogue!



Latest articles