Cold Metalworking Processes TSM 233 Unit 10

TSM 233 Metallurgy and Welding Processes Cold Metalworking Those metalworking processes where the base metals are not heated nor allowed to become heated above the ambient temperature. Processes include: Bending Shaping Drilling Threading Riveting Cutting, including shearing Fastening, such as with screws, bolts. Punching, as in punching a hole.

TSM 233 Metallurgy and Welding Processes Drilling The process of drilling holes in metal. Twist drills are driven by a power drill, drill press, hand drill, etc. Drills can powered by compressed air, electricity, and mechanical means Drill sizes: Fractional inches (1/4”, 3/32”, etc.) Numbered index (1,2,3….) Lettered index (A, B, C…..) Decimal inches (0.100”, 0.150”…..) Metric (0.50mm, 2.50 mm……)

TSM 233 Metallurgy and Welding Processes Sharpening a Standard Twist Drill Bit. Three critical cutting angles: Cutting lip (59 degrees from the centerline of the drill bit) Cutting chisel point ( degrees to the cutting lip when viewed from the top of the drill bit) Cutting Clearance ( degrees) Use a twisting, forward pushing movement up the circular grinding wheel at the cutting lip angle (59 degrees). Twist drill bit grinding tools are readily available.

TSM 233 Metallurgy and Welding Processes Threading The process of putting threads on or into a piece of metal. Dies put threads on the outside of a round stock of metal. Taps put threads on the inside of a hole drilled in a stock of metal. Common types of threads: Standard Bolt -Coarse Standard Bolt - Fine Metric Bolt Pipe Machine Fitting

TSM 233 Metallurgy and Welding Processes Threading Metals Tapping Holes: Determine the type and size of thread. Drill the proper size hole. Use the proper type and size tap, cut the threads using a cutting oil if needed. Clean the threaded hole. Threading Round Metal Stock: Determine the type and size of thread. Grind or file a slight bevel on the end of the stock. Use the proper type and size die, cut the threads, using a cutting oil if needed. Clean the threaded stock.

TSM 233 Metallurgy and Welding Processes Fasteners Rivets: pop rivets pin rivets Screws machine crews self-tapping screws Bolts machine carriage bolts stove bolts

TSM 233 Metallurgy and Welding Processes Crimp Fastening Metal Crimp Seams: the edge of a sheet of metal is bent back upon itself to secure a second sheet of metal. Notching: A notch is sheared in the metal, and bent back to secure the second sheet of metal.

TSM 233 Metallurgy and Welding Processes Grinding and Sanding Metals Abrasives are used to grind and sand metals. Grain refers to the size of grinding wheel abrasive materials. The grit refers to the size of sanding abrasive materials. Grain and grit are based upon the sieve size that the material will pass through: #120 = 120 meshes of screen per inch.

TSM 233 Metallurgy and Welding Processes Polishing Metal Metal can be polished using a metal polishing compounds and a high speed polishing/buffing pad. Very similar to using an electric polisher for a waxing and polishing an automobile. Match the type of polishing compound and pad to the type of metal and the desired finish.

TSM 233 Metallurgy and Welding Processes Website Use the McMaster’s website to explore all types of fasteners, taps, dies, abrasives, polishers, etc. for metal.