GB267587A - Process of manufacture of cutting, piercing, and the like instruments - Google Patents

Abstract

267,587. Ignatieff, A. Dec. 12, 1925. Compound forms; drills and cutters; saws; milling-cutters; taps; screwing-dies; files; lathe and like tools.-In making cutting, piercing and like instruments having a cutting edge formed with two faces, the non-working face is covered with at least two layers of graduated hardness so as to retain the cutting-edge sharp during use. A lathe tool has hard layers 1 welded or otherwise fixed as by clamps and screws to the rear edge of the tool 2. A similar tool or straight tool for planing or shaping may similarly have hard layers on its rear edge. A saw, Fig. 4, or with finer or broader teeth a file, has the hard layers 1 on the rear face of the teeth. In another form of saw having two rows of parallel teeth, Figs. 5 and 7, a soft central layer is covered on both sides with layers of gradually increasing hardness and is then corrugated and planed on its outer surfaces to form hard layers 1 extending in the form of bars or strips from the points of the teeth. This form of saw may be made by casting the bars on to straight layers. A circular cutter of the hob type has its spiral faces covered with the cutting layers. A helical crown borer, Fig. 10, with a conical central channel has four conical teeth and four helical multiple cutting layers 1. A twist drill with cutting layers 1 on the shank 5 has a conical head 6 secured thereto having the cutting layers 1 on its two threads. The rear ends of the head abut against the projections on the shank. Multiple toothed broaches, reamers, helicoidal milling cutters, circular saws or files, screw-cutting taps and dies may be similarly provided with hard cutting layers. A screw chaser, Fig. 13, has cutting layers 1 on its non-working faces. The cutting layers may be applied by electrodeposition or by spraying. Specifications 13011/13, 207,822, [both in Class 83 (iii), Metals, Cutting], and 261,166 are referred to.