Yamawa taps for the mold and die industry provide a reliable solution for achieving high-quality thread surfaces in a wide range of hard and ultra-hard materials typically used in this sector.
The best option for manual carbide taps in high-hardness steels are the EH-CT taps, specifically designed for threading materials from 45 to 55 HRC, such as high-alloy steels (95 MnWCr 5 KU), hardened tool steels (X 155 CrVMo12 1 KU) and tool steels (X 40 CrMo 5 1 1 KU).
They can also be used on machining centers equipped with synchronous feed systems.

Tip Diameter

The tip diameter of the EH-CT taps is designed to be as close as possible to the maximum minor diameter of 6H internal threads and is larger than that of standard tips.
Please note that if the internal thread class is specified as “6H or class 2,” make sure to drill the hole as close as possible to the maximum minor diameter allowed by the thread tolerance.
For more information on the importance of hole size, see this technical tip.

Chamfer Length

The chamfer length of EH-CT taps is 5 threads: adjust the hole depth to a value greater than the tap’s chamfer length.
Warning: if the tap begins to rotate without cutting due to chip accumulation at the bottom of the hole, the chamfered threads of the EH-CT tap may chip.

The recommended cutting speed when using EH-CT taps is approximately 4 m/min or lower.

When the challenge is threading ultra-hard materials (hardness above 55 HRC), we recommend using UH-CT carbide taps.