| 摘要 |
PURPOSE:To enable the radiation of heat due to cutting, reduce cutting resistance and improve the cutting performance of a drill reamer by forming nicks aslant for an axial line at the side of a drill tip on reamer burnishing cutting edges in the drill hammer of cemented carbide. CONSTITUTION:This drill hammer 1 has a cutter part 4 with two rows of lands 2 and helical flutes 3. A plurality of reamer burnishing cutting edges 5 and reamer burnishing chip discharge grooves 6 are formed on each land 2. The reamer burnishing cutting edges 5 are formed by a number equal to or above the number of the reamer burnishing chip discharge grooves 6. Nicks 7 are formed for the reamer burnishing cutting edges 5 totalling six over the entire cutter part 4. The nicks 7 are so formed as to incline for the axial line of a drill tip. The nicks 7 for the reamer burnishing cutting edges 5 are disposed with a dislocation Z equal to (X+Y)/N, where X is a cutting edge width between nicks 7 in the same burnishing cutting edges 5, Y is a nick width and N is the number of rows of the burnishing cutting edges 5 formed on the cutter part 4, respectively. |
