| 摘要 |
PURPOSE:To make it possible to perform cross-thinning grinding, by providing first and second setting means for setting a drill so that is relief angle is at least 40 deg. while its rake angle is less than 10 deg. and its chisel edge angle is about 135 deg.. CONSTITUTION:A drill to be ground is set on a setting bed inclined at a predetermined angle with respect to the direction of the axis (q), and a chuck bed 31 is rotated about the axis (s) of a chuck setting section 35 as a rotating center as shown by 31a in order to set its relief angle to at least 40 deg.. Accordingly, a turning angle due to the rotation in the direction Q about the axis (q) attains the relief angle of 40 deg.. However, since the chisel edge angle and the rake angle would be changed as it is, the chuck bed setting section 3 is rotated about the axis (t) as the rotation center in the direction T, and therefore, it is set such that the chisel angle is about 135 deg.. While the rake angle is less than a limited value of 10 deg.. Thus, it is possible to perform cross-thinning grinding due to the rotation and movement in the direction X of the feed bed. |
