Cutting tool expert Union Tool leads in the domain of hard milling. Here, the Japanese manufacturer demonstrates the optimal way of milling a solid block of 1.2344 steel, tempered to 54HRC to 100mm from each side. The classic method of machining hard materials or hard milling is an alternative to grinding and electrical discharge machining (EDM). Hard materials are classified in two categories. The first, soft materials that have undergone hardening by a thermal or thermo-chemical treatment and the other is naturally hard materials like carbides, ceramics, minerals and many sintered materials. Materials with a hardness between 35 to 70 HRC are classified as hard. For steel, a minimum carbon content of 0.4% is essential for steel to harden sufficiently after tempering. Union Tool, headquartered in Japan, has a Swiss-based subsidiary, Union Tool Europe, located close to Neuchâtel, a stone throw from Borotec that houses the European technical centre of the Japanese manufacturer. The demonstration workpiece described in this article was machined right here – a solid block of 1.2344 steel (X40CrMoV5-1) tempered to 54HRC to 100mm from each side. Prior to detailing the machining proces...