If, however, a mechanic concentrates on just one machine to the point of specialization, he or she becomes a lathe hand or operator, a milling machine hand or operator, or a grinder hand or operator. Such operators could specialize in filing, scraping, fitting, assembling, and the like and thus become a bench hand, an assembler, or a fitter hand.
Here we must make a distinction between those highly skilled specialists and the machine operator, an attendant whose function is to keep an automatic machine tool loaded and to make sure the finished piece goes on its way. These operators usually are employed in large, high production shops like automobile plants. However, somebody else must get these automatic and semiautomatic machines ready or set up for production, grind and set the tools, instruct the operator, and make sure the work comes out to measurements. This person is called a set-up person.
Another highly skilled group of mechanics is the instrument makers. They not only have an all-around mechanical ability, in the same class as the toolmakers, but also a good technical background. In working with scientists, inventors, and experimenters, they must be able to translate their ideas into working models from sketches, diagrams, and verbal instructions. Instrument makers must be able to work with very little supervision.
Many shops employ inspectors, highly skilled in the use of measuring instruments, to supervise all the work going through and make sure that all measurements are up to the specifications.
In addition to all these traditional trade categories, new and specialized jobs have arisen as a result of the widespread use of machine tools with electronically controlled, automatic cycle devices known as numerical controls. This technology has spread rapidly with a corresponding rise in job opportunities. Other new machine tools that do not use the traditional methods of cutting and shaping metals but rely on electrical discharges and chemical action have been developed. These tools require special techniques in set-up and operation.
Another departure from the conventional methods of metal-working is the introduction of the laser beam. Powerful laser beams (concentrated light rays), set up in a machine tool can cut holes and shapes to exact specifications. Guided by computerized control circuitry, the operation can be entirely automatic and form part of a production line. There are many advantages from the use of laser beams, for example, the edges of the holes and shapes thus produced can be used with no further machining.
The Dictionary of Occupational Titles, published by the U.S. Department of Labor, describes a machinist in this way:
Machinist, all around: sets up and operates a variety of machine tools and fits and assembles parts to fabricate or repair machine tools and maintain industrial tools, applying knowledge of mechanics, shop mathematics, metal properties, layout and machinery procedures; observes and listens to operating machines or equipment to diagnose malfunction and determines need for adjustment or repair, studies blueprint, sketch, machine part or specifications to determine type and dimensions of metal stock surfaces, using such measuring and marking devices as calibrated ruler, micrometer, and calipers; uses machine tools such as lathe, milling machine, borer, grinder, drill press and hand tools such as scraper and files and such measuring devices as vernier, height gauge, and gauge blocks.
There are other specialized jobs in machine shops, but the ones mentioned in the preceding paragraph are the ones usually meant when the overall term machinist is used.
REQUIREMENTS FOR SUCCESS
Before going into a detailed description of the various machine shop trades, it might be best to consider the general factors necessary for success in the field and also the general working conditions found in the shops.
If we were to select the most important personality trait for persons working in the machine shop trades, it might be a genuine liking for working with tools and machinery and for making and repairing all kinds of devices. If you possess this as well as a certain amount of manual dexterity, then you can confidently consider a career in a machine shop. Of course, you must also be able to tolerate dirt, grease, noise, and certain other so-called unpleasant aspects of the work place. It is true that modern shops are usually comparatively clean and well-lighted and have adequate working and sanitation facilities. Still, a certain amount of dirt and noise is unavoidable. If you shrink from getting your hands and clothes dirty and greasy and from occasional scratches, burns, and bruises, then perhaps a machine shop is no place for you.
You also need to be in good physical shape-a sound body, good eyesight, and plenty of stamina. On many jobs you may have to stand all day; others may require lifting of tools, equipment, and metal parts. For close work with fine precision measuring instruments, you will be using your eyes constantly. Of course, it is true that, given the proper spirit and incentive, handicapped persons also can become good machinists. If you are handicapped, however, give serious thought to your career choice and be sure to get the advice of medical and technical experts.