THROW-AWAY DRILL

摘要

The throw-away drill includes a cutting edge portion (31) for cutting a work and shank portion for fitting to a predetermined position of a cutting tool, and in which, the cutting edge portion is detachably and mechanically coupled to the shank portion (32). The cutting edge portion and the shank portion have complementary fitting portions and slits are formed in either one of the cutting edge portion and the shank portion. When the cutting edge portion and the shank portion are fitted to each other, the opposed surfaces to these slits (34,39) move away from each other and undergo elastic deformation, so that the resulting elastic force fixes the cutting edge portion to the shank portion. Accordingly, screwing or the like is not necessary and the cutting edge portion and the shank portion can be coupled by mere press-in operation. Accordingly, working efficiency can be improved during the assembly process. A surface coated ultra-hard alloy is used as the material of the cutting edge portion, and steel as the material of the shank portion. Therefore, the cutting edge is excellent in wear resistance, adhesion resistance and heat crack resistance and the shank portion a relatively low-coat throw-away drill. @(56pp Dwg.No.6/23)@