| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a chuck having an uneven clamping face at a low cost, prevented from possibly causing the slide of a rod material in the chuck during machining the rod material. SOLUTION: A chuck 10 has a plurality of grooves 26, 28, crossing each other while extending torsionally to the axis of a slotted portion 14, in a rod material clamping face 24 of each clamping member of the slotted portion 14. The grooves 26, 28 consist of a desired number of screw grooves 26 in a right female screw and a desired number of screw grooves 28 in a left female screw, respectively. A number of protruded portions 30 rhomboid-shaped in a plan view for preventing the slid of a rod material is thus regularly formed all over the rod clamping faces 24 of three clamping members 20 of the slotted portion 14. Each of the screw grooves 26, 28 is quickly and accurately formed in a cutting process using a female tapping bite.
|
