| abstract |
PCT No. PCT/JP90/01670 Sec. 371 Date Aug. 22, 1991 Sec. 102(e) Date Aug. 22, 1991 PCT Filed Dec. 21, 1990 PCT Pub. No. WO90/09698 PCT Pub. Date Jul. 11, 1991.A throw-away tipped drill has an insert removably connected to a shank for cutting a workpiece. The insert (31) and the shank (32) have mutually engaging surfaces respectively, and a slit (34, 39) is formed either in the insert (31) or in the shank (32) for mounting the insert to the shank, whereby the insert (31) is fixed to the shank (32) by an elastic force which is caused by an elastic deformation upon mutual movement of opposite surfaces of this slit (34, 39) in engagement of the insert (31) and the shank (32). Therefore, the insert (31) and the shank (32) are coupled by simple press fitting without any requirement for a screw or other connection, whereby the assembly is improved. The cutting edge of the insert (31) has an excellent wear resistance, adhesion resistance and thermal cracking resistance and the shank (32) has an excellent toughness while the drill is relatively low in costs, by employing surface-coated cemented carbide as the material for the insert while employing steel as the material for the shank. |