Patent ID: 8747032

Claim:
A tool for machining a workpiece, comprising: a tool body having a tool body through-bore opening into an accommodating recess; a cutting tool having a cutting edge and a cutting tool through-bore; a fastener, wherein the fastener fastens the cutting tool in the accommodating recess of the tool body, said fastener having a clamping bush provided with a clamping bush internal thread and a clamping screw provided with a clamping screw external thread corresponding with the clamping bush internal thread, wherein the clamping screw is configured to be inserted from a first side of the tool through the cutting tool through-bore into the tool body through-bore and screwed to the clamping bush, wherein the clamping screw is configured to be inserted from a second side of the tool opposite the first side through the tool body through-bore into the cutting tool through-bore and screwed to the clamping bush; and an anti-rotation locking means which prevents rotation of the clamping bush about a longitudinal axis thereof when the clamping screw is being screwed to the clamping bush and when the clamping screw is being unscrewed from the clamping bush, wherein the anti-rotation locking means is formed by a tapered surface on the clamping bush and/or by a tapered surface on a head o f the clamping screw where the tapered surface on the clamping bush and/or the tapered surface on the head of the clamping screw is adapted to at least part of the tool body through-bore and/or adapted to at least a part of the cutting tool through-bore.