Tool Manufacture
Common Cutting Operations
Toolmark Identification
1. Abrasive machining - The use o abrasives rather than high-speed steel or tungsten carbide cutting tools. 2. Broaching - Finishing surfaces by drawing or pushing a cutter called a broach entirely over and past the surface. A broach has a series of cutting teeth arranged in a row or rows, graduated in height from the teeth that cut first to those that cut last. 3. Reaming - To widen the opening of a hole, Countersink: to enlarge or dress out a hole with a reamer, to enlarge the bore of a gun. 4. Drilling - Cutting holes in metal with a twist drill. Drills also use a variety of other cutting tools to perform the following basic hole-machining operations: (1) reaming, (2) boring, (3) counterboring, (4) countersinking, and (5) tapping internal threads with the use of a tapping attachment. 5. Planing - Metal-cutting machining in which the workpiece is firmly attached to a horizontal table that moves back and forth under a single-point cutting tool. The tool-holding device is mounted on a crossrail so that the tool can be fed (moved) across the table in small, discrete, sideward movements at the end of each pass of the table. 6. Boring - Producing smooth and accurate holes in a workpiece by enlarging existing holes with a bore, which may bear a single cutting tip of steel, cemented carbide, or diamond or may be a small grinding wheel. 7. Milling - Cutting metal by feeding against a rotating cutting tool called a milling cutter; milling machines cut flat surfaces, grooves, shoulders, inclined surfaces, dovetails, and T-slots. Various form-tooth cutters are used for cutting concave forms and convex grooves, for rounding corners, and for cutting gear teeth. 8. Turning - Turning operations involve cutting excess metal, in the form of chips, from the external diameter of a workpiece and include turning straight or tapered cylindrical shapes, grooves, shoulders, and screw threads, and facing flat surfaces on the ends of cylindrical parts. 9. Shaping - Shaping and planing operations involve the machining of flat surfaces, grooves, shoulders, T-slots, and angular surfaces with single-point tools. |
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