| 摘要 |
<p>A gun-drill (20) comprises a cutting head (22) detachably secured to a shank (24),having a common longitudinal axis (A) and comprising mating peripheral surfaces.A shank coupling portion (78) comprises a forwardly tapering shank fixationsurface (86) is formed at a front end of the shank, and a cutting-head couplingportion (58) comprising a forwardly tapering cutting-head fixation surface(68) is formed at a rear end of the cutting-head. Both the shank and the cutting-headcoupling portion extend over a peripheral coupling angle of more than180 . The shank and the cutting-head are assembled by positioning the cutting-headleading face in front of the shank trailing face, slidably inserting the cutting-headcoupling portion into the shank coupling portion laterally to the axis of rotationA and rotating the cutting-head relative to the shank in a direction opposed tothe direction of rotation R so that the cutting-head coupling portion and theshank coupling portion interlock co-axially.</p> |
