| 摘要 |
A cutting head is formed at one end of the shank and comprises a cylindrical member having an annular wall defining a circular cutting edge. A cutting blade having a sharp cutting edge extends from adjacent a centering point to adjacent the cutting edge. The cutting head is formed of a first material and the cutting blade is formed of a second material. The cutting blade is brazed to the cutting head. A method of making a drill bit comprises investment casting a shank and a cutting head of a first material. A pocket is formed that extends to the cutting edge. A coupon of a second material is brazed in the pocket. A sharp edge is ground in the coupon. |
