摘要 |
A metal-cutting mechanism includes an externally threaded screw and a set of non-rotatable insert holders spaced apart equidistantly along an axis of the screw. There are at least first, second, third, and fourth holders arranged axially in succession. The first holder is axially fixed. The second, third and fourth holders are axially movable relative to the first holder. The screw is rotatable relative to the second, third, and fourth holders and is connected thereto such that in response to each revolution of the screw, the second holder is moved in a first axial direction by a distance x, the third holder is moved in the first axial direction by a distance 2x, and the fourth holder is moved in the first axial direction by a distance 3x, whereby the equidistant spacing between the holders is changed by the distance x. |