Trepanning tool for trepanning tapered metal shapes

摘要

983,249. Making hollow or cupped articles; turning; breaking. BRUSH BERYLLIUM CO. June 14, 1961 [Sept. 20, 1960], No. 21444/61. Headings B3A, B3B, B3E and B3T. A billet is subdivided into a number of workpieces having conical walls by forming spaced coaxial conical kerfs in the billet and separating the workpieces from the billet. In this way frusto-conical shells are formed from a hollow billet or cup-like or conical workpieces are formed from a solid billet. The separating is performed by cutting or breaking or by continuing the kerfs through the wall of the billet. Kerfs are formed in a beryllium billet 1, Fig. 1, secured on a rotating table T by a trepanning tool 10 mounted on a slide 11. No lubricant is used and the waste chips are extracted by suction into a container 54. The tool 10, Figs. 5 and 7, has a thin elongated body 20 of shallow elongated concavo-convex cross-section with a shank 22 at one end and a cutting head 32, Fig. 10, secured to the other end. The cutting tip 39 is welded or brazed to the head 32 and has cutting edges 41, 43 preferably shaped as in Fig. 10. Carbide pads 45 secured to the body 20 locate the body within the kerf. A suction tube 50 is attached to the leading edge of the body 20 to extract the waste chips. Each kerf may be cut by two tools spaced 180 degrees apart. The cutting tips are shaped as shown in Figs. 13 and 14 so that one tool cuts the central portion of the kerf while the other cuts the edge portions. It is stated that the kerfs can be cut outwardly from the inner periphery of a hollow billet. Specification 842,226 is referred to.