If you decide to enter one of the metal-working trades, you should take training for the trade, rather than for some job in the trade. Learn the trade rather than simply how to operate some one machine, or how to do one simple task, and you can then accept promotion in the trade, and make good at any job in it.
What Metal Workers Produce.
Everything in metal from a minute screw to a locomotive engine—from a tin can to a great gun casting. They produce machines to produce machines, and with tools and machines which they themselves produce, they produce every sort of metal product or metal part of a product, including machinery and equipment for the farm, the factory, and the home.
Nearly every article of common use, whether made of metal or of other material, is more or less a machine product, and practically the whole machinery for producing nonmetal as well as metal products is originally the product of the metal trades.
Specifically the product of a machine shop may be a complete machine, a rebuilt or repaired machine or machine part sold to other firms. For such a product raw material of cast iron, sheet iron, steel of varying degrees of hardness, wrought iron, brass, or bronze, comes from the foundry or from a stock department in which are kept sheets, steel bars, castings and forgings. Much of the labor in some shops must be employed in producing shop equipment, including formed cutters, reamers, drills, and various metal working tools made in the shop.
Processes.
Molding, which is a basic operation in the metal industries, is a comparatively simple process especially when standardized parts are being cast, and it is not necessarily heavy work since castings in various metals, may be of any size and weight. Molten metal, pure or alloyed, is poured into a mold formed by a pattern in sand or loam. In many instances castings must be finished by machinery.
When a part is to be subjected to hard usage or to severe strains and stresses, forging or hammering rather than casting may be the process employed in shaping it. Drop forgings are made by means of automatic power hammers and dies. With few exceptions forgings, also, must be finished by machining.
Sheet-metal workers lay out work on sheet metal, cut it, shape or bend it, and solder, rivet or weld it into various forms, such as are required in building up ornamental cornices for buildings, or in constructing hot-air heating apparatus, or in manufacturing filing cases, various sorts of containers, and many other articles. Some of the work is outside work, but an increasing number of processes are being performed in the shop with the use of machinery. Metal stamping and electric welding machines are used to form and weld together parts of, for example, automobile bodies, doors, and fenders.
Of all the metal-working trades, that of the machinist is the most varied in its hand and machinery processes, although many workmen never learn more in the trade than how to operate some one automatic machine, or how to do some one simple task. In general the machinist should know how to operate all of the machinery of his trade, and in addition he must acquire skill of hand in metal working, and especially in the processes of building, repairing, assembling, and erecting every sort of engine and machine.