A customer tapping Cast Iron engine blocks was looking for ways of reducing the cost per part.The tap design was considered correct for the application but we believed a change in material and coating would be of benefit.

The “original” tool was manufactured in a conventional 5% Cobalt High Speed Steel with a Titanium Nitride coating. Tool life had been set at 4,500 threads.

Unfortunately a review of the process showed that it was not suitable for carbide tapping (due to limitations of the machine). Therefore, we chose to produce trial taps in a superior grade Powder Metallurgy steel supplied by Erasteel and change the coating to Balzers Hardlube, whilst making only minor changes to the design.

In this instance, the tool life was doubled. The cost of the tap only increased by 20% and the customer was more than pleased with his 33% reduction in tapping cost.