Abstract: A metal-working tool with augmented electrical and thermal conductivity. In a metal-working tool, such as a drill bit 10, having at least one groove 14 behind a cutting edge 34, a coating 12 is placed on the surface of the groove 14. The coating 12 is formed from a material having a higher electrical conductivity than the material from which the bit 10 is formed and, preferably, the coating material also has a higher thermal conductivity. The coating 12 reduces the resistance of the bit 10, thereby reducing the heating of the cutting edge 34. The improved thermal conductivity also reduces the heating of the cutting edge 34.

Abstract: A hot metal-working tool 10 using electrical resistance heating. Metal-working tool 10 comprises seat 12, cutting insert 14 and chipbreaker 16. Electrical current source 35 provides current which flows between metal working edge 30 of insert 14 and the shear zone 80 of a workpiece 72 during the machine operation. Cutting insert 14 comprises two structural components, one of which 26, contacts chip 82 thereby providing a second path for current flow between tool 10 and shear zone 80. Shear zone 80 may thus be heated by current not passing through metal-working edge 30. The invention also provides for the flow of coolant fluid through internal passages in tool 10. The coolant fluid removes heat from metal working region 28 and is then discharged to bathe the region proximate metal working edge 30.