Verfahren und Vorrichtung zum Ausbilden eines Lochs in einem Werkstück

摘要

A boring apparatus which includes a rotatable cutting head used to cut a hole in a workpiece. The cutting head is mounted on an axially movable support, and is rotatable about and reciprocally movable along the axis between a forward cutting position, to engage and cut the workpiece, and a rearward position spaced from the workpiece. Cutting is performed by a cutting blade which is spaced radially from the axis, and which is movable relative to the rest of the cutting head by a blade advance mechanism. During cutting operation, the blade advance mechanisms move cutting blade both forwardly and radially inwardly through the workpiece wall, in the same direction at which the blade is inclined. The hole is thus formed by lowering the cutting head and then rotating the cutting blade as the blade advance mechanism moves the blade at an angle through the workpiece. Both the resulting hole and waste plug cut from the workpiece produced by the angled movement of the blade have complementary tapered edge portions, with the result that the plug will have a portion with a diameter which is larger than the smallest diameter portion of the hole.