| 摘要 |
PROBLEM TO BE SOLVED: To improve the life of a tool by reducing a thrust load without making a core thickness small. SOLUTION: Since a cutting face 48 of an axis side cutting blade 46 and an inclined surface 52 are smoothly connected with no stepped part, the discharge performance of the chip cut by the axis side cutting blade 46 is improved, the thrust load is reduced and the life of the tool until the tool is damaged or re-grinding is improved. Particularly, since the cutting face 48 is ground by a side surface 56 of a web thinning grinding wheel and the inclined surface 52 is simultaneously ground by an outer peripheral surface 58 provided against the side surface at an angleαof approximately 100°, the cutting face 48 and the inclined surface 52 are smoothly connected with no stepped part corresponding to an angular shape of the web thinning grinding wheel 54. Whereas, troublesome positioning is not required as compared with the case where the inclined surface 52 is ground at a separate step from web thinning and a number of machining steps and a machining cost are reduced. Thereby, the drill 10 is manufactured at a low cost. COPYRIGHT: (C)2004,JPO |
