| 摘要 |
PURPOSE:To prevent seizure or binding from occurring as well as to aim at improvement in the accuracy of finishing, by installing a lubrication passage, to be opened to an inner surface of a support hole, in a supporting body which allows a boring bar to be pierced through and supports it rotatably. CONSTITUTION:A bearing member 82 of a boring bar 7 is tightly attached to a jig body 75 with a bolt. A space hole 161 is installed in this bearing member 82, and an inner sleeve 162 as a cylindrical supporting body having a support hole 83 capable of piercing the boring bar 7 through, is pressed in this space hole 161. An annular groove 163 is installed in an inner surface of this space hole 161, and a guide hole 166 being interconnected to this groove is installed therein, whereby cutting oil is led into this hole by way of a feed oil pipe 69. With this cutting oil, the bar 7 is supported on the sleeve 162 via this oil according to rotation of the boring bar 7. Therefore, seizure or binding is preventable even at the time of high speed rotation of the bar 7.
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