BOORGEREEDSCHAP.

摘要

A hole-forming tool comprising a body adapted for being driven in rotation and including a front portion having an axial bore. A plurality of cutting plates are removably secured to the front face of the front portion of the body for cutting a ring of material from a metal workpiece while leaving a non-cut core in the axial bore. The body carries an ejector in the bore for ejecting the core at the end of the cutting operation. The ejector can be a slidable member which is resiliently urged into the bore and which opposes the core to effect displacement thereof from the workpiece when the tool has completely cut through the workpiece. A system is also provided for axially distributing a lubricating liquid through the bore to the cutting plates.