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Precision machinists use machine tools, such as drill presses, lathes, and milling machines, to produce metal parts that meet precise specifications. They combine their knowledge of metals with skillful handling of machine tools to make precision-machined parts for automobiles and other vehicles. Approximately 28,000 precision machinists are employed in the motor vehicle and parts manufacturing industry.
The modern era of producing metal parts accurately and according to specifications began with the invention of the steam engine by James Watt in the latter part of the 18th century. During this same period, John Wilkinson invented the boring machine, which enabled the precise cutting of cylinders for Watt’s engine. Also during this time, Henry Maudslay developed a lathe to precisely cut screw threads.
Many other methods of production were developed during the industrial revolution. In Great Britain, metal molds and machine-powered engines were used to produce items that had originally been handcrafted. These new processes lowered costs and sped up production schedules. At about the same time in the United States, Eli Whitney was using tools and machines to make gun parts with such accuracy that they were interchangeable.
This interchangeability of machine-produced parts became the basis for modern mass production. Throughout the 19th century, more specialized and refined metalworking machines were designed.
The electric motor became widely used as a source of power, which spurred further improvements in manufacturing.
The workers who used these machines to create parts—machinists and machine tool operators—developed into a specialized group who combined machining knowledge with skillful handiwork. By 1888, there were enough machinists in various industries to organize their own union.
In the 20th century, the automobile industry was probably the largest single force in the development of machinery and demand for machinists. Technological developments, such as numerical control machinery and computer-aided design applications, have continued to spur progress in machining operations.
These developments have also changed the jobs of machinists. Now workers set manual and computer-controlled machine tools to cut and contour metal into intricate shapes. They use lasers, intricate measuring machines, and modern imaging equipment to check dimensions. Though much of machinists’ work is still done by hand, their profession has evolved into much more of a science than a craft.
Precision machinists are trained to operate most types of machine tools that shape pieces of material—usually metal—to specific dimensions. The work done by machine tools can be classified into one of the following categories: cutting, drilling, boring, turning, milling, planing, and grinding.
After receiving a job assignment, the machinist’s first task is to review the blueprints or written specifications for the piece to be made (for example, brake rotors, crankshafts, and cylinder blocks). Next the machinist decides which machining operations should be used, plans their sequence, and calculates how fast to feed the metal into the machine. When this is complete, he or she sets up the machine with the proper shaping tools and marks the metal stock (a process called layout work) to indicate where cuts should be made.
Once the layout work is done, the machinist performs the necessary operations. The metal is carefully positioned on the tool, the controls are set, and the cuts are made. During the shaping operation, the machinist constantly monitors the metal feed and the machine speed. If necessary, the machinist adds coolants and lubricants to the workpiece to prevent overheating.
At times machinists produce many identical machined products using a single machine; at other times, they produce one item by working on a variety of machines. After completing machining operations, they may finish the work by hand using files and scrapers, and then assemble finished parts with hand tools.
Machinists’ work requires a high degree of accuracy. Some specifications call for accuracy within .0001 of an inch. To achieve this precision, they must use measuring instruments such as scribers, micrometers, calipers, verniers, scales, and gauges.
In the past, machinists had direct control of their machines. How ever, the increasing use of numerically controlled machines and , in particular, computer numerically controlled machines, has changed the nature of the work. Machinists may now work alone or with tool programmers to program the machines that make the parts. They may also be responsible for checking computer programs to ensure that the machinery is running properly.
Some machinists, often called production machinists, may pro duce large quantities of one part. Others produce relatively small batches of parts or even one-of-a-kind items. Finally, maintenance machinists specialize in repairing machinery or making new parts for existing machinery. In repairing a broken part, the maintenance machinist might refer to existing blueprints and perform the same machining operations that were used to create the original part.
For entry-level jobs most employers prefer high school or vocational school graduates. To prepare yourself for a metalworking career, you should take courses in algebra, geometry, mechanical drawing, blueprint reading, machine shop, drafting, and computer applications. If available, classes in electronics and hydraulics can also be useful.
To become a precision machinist, you need to either complete for mal training through an apprenticeship or postsecondary program or receive extensive on-the-job training. Apprenticeships generally consist of four years of shop training combined with related classroom instruction. During shop work, apprentices learn filing, dowel fitting, and the operation of various other machine tools. The operation and programming of computer-controlled tools are also covered. Classroom instruction includes industrial math, blueprint reading, precision machining, computer numerical control concepts, machine tool technology, and manufacturing processes.
You can also enter the field directly from high school or vocational school and receive on-the-job training. In this case newly hired workers are supervised by experienced machinists, training with one machine to another. Trainees usually begin as machine operators. Then, as they show the necessary aptitude, they are given additional training on the machines they are operating. Further instruction in the more technical aspects of machine shop work is obtained through studying manuals and classroom instruction. The amount of progress depends on the skill of the worker.
Certification and Licensing
Increasingly prospective machinists receive postsecondary training through community or technical school programs. Many training facilities have incorporated a set curriculum established by the National Institute for Metalworking Skills (NIMS). After students complete the established courses and pass performance evaluations and written exams, they receive a formal recognition of competency, a NIMS credential. This designation aids in their job search by confirming their skills and knowledge of the metalworking field.
A precision machinist must have an aptitude for using mechanical principles in practical applications. Knowledge of mathematics and the ability to understand and visualize spatial relationships is also needed to read and interpret engineering drawings.
Machinists must have excellent manual dexterity, good vision and hand-eye coordination, and the concentration and diligence necessary to do highly accurate work. Because their work requires a great deal of standing, lifting, and moving, machinists must also be in good physical condition. Finally, it's necessary for machinists to be able to work independently in an organized, systematic
To observe precision machinists at work, ask a school counselor or teacher to arrange a field trip to a machine shop or an automotive manufacturing plant. You could talk to a machinist personally to learn the pros and cons of their job. Another excellent opportunity to explore this occupation could be through a part-time or summer job in a machine shop or an automotive plant.
Approximately 28,000 precision machinists are employed in the motor vehicle and parts manufacturing industry. They are employed by production engine re-manufacturers, machining shops, automotive manufacturers, and auto parts supply houses with machine shop services.
To find job leads, try searching newspaper classified sections or contact potential employers directly to ask about opportunities. Other sources of information are state employment offices, the U.S. Department of Labor’s Bureau of Apprenticeship and Training, and union headquarters, such as the International Association of Machinists and Aerospace Workers or the International Union, United Automobile, Aerospace, and Agricultural Implement Workers of America. If you receive formal postsecondary training from a community college or technical school, you may find job assistance from the school’s career counselors or career services offices.
If you enter the field directly from high school or vocational training, you may be required to start as a machine shop helper or tool operator. These entry-level jobs will help you to develop the experience and technical skills necessary to become a precision machinist.
After several years of developing their skills, precision machinists have many advancement opportunities. They may choose to specialize in niches such as tool and die design or fabrication, sales, or instrument repairing. In large production shops, machinists have the opportunity to become setup operators or layout workers.
Those who have good judgment, excellent planning skills, and the ability to deal well with people may advance to supervisory positions, such as shop supervisor or plant manager. With additional education, some machinists may become tool engineers. Finally, some skilled and experienced workers eventually go into business for themselves.
The median hourly salary for precision machinists working in motor vehicle parts manufacturing was $18.27 (or $38,000 annually) in 2006, according to the U.S. Department of Labor. The lowest 10 percent of all precision machinists made less than $10.29 an hour (or $21,400 annually), and the highest 10 percent earned more than $25.31 per hour (or $52,640 annually).
Benefits usually include paid holidays and vacations; life, medical, and accident insurance; and retirement plans.
Precision machinists generally work 40 hours a week; however, working night and weekend shifts as well as overtime has become more common in the industry as employers increase their hours of production.
Machinists work indoors in shops that are fairly clean, with proper lighting and ventilation. Noise levels are often quite high because of the nature of power-driven machinery. In addition, machining work can be physically strenuous at times. Machinists are usually on their feet for most of the day and are required to lift and maneuver heavy work pieces. For eye protection, they wear safety glasses while using machine tools.
Employment for precision machinists employed in motor vehicle and parts manufacturing is expected to decline through 2016, according to the U.S. Department of Labor. Automation is contributing to this slower growth rate. The increased use of computer- controlled machine tools improves efficiency. Therefore, fewer machinists are needed to accomplish the same amount of work.
Even so, openings will arise from the need to replace machinists who retire or transfer to other jobs. In recent years, employers have reported difficulty in attracting skilled workers to machining occupations. If this trend continues, good employment possibilities should exist for candidates with the necessary technical education and skills.
Layoffs are often a factor affecting employment of machinists. When the demand for automobiles and other motor vehicles declines, workers’ hours may be either shortened or reduced completely for days, weeks, even months at a time. There is somewhat more job security for maintenance machinists because machines must be cared for even when production is slow.
FOR MORE INFORMATION
For information on apprenticeships, contact:
International Association of Machinists and Aerospace Workers
9000 Machinists Place
Upper Marlboro, MD 20772-2687
International Union, United Automobile, Aerospace, and Agricultural Implement Workers of America
8000 East Jefferson Avenue
Detroit, MI 48214-2699
For information about skill standards and obtaining NIMS credentials, contact
National Institute for Metalworking Skills (NIMS)
10565 Fairfax Boulevard, Suite 203
Fairfax, VA 22030-3135
For information about training and opportunities in the precision machining and metalworking industries, contact the following organizations:
National Tooling and Machining Association
9300 Livingston Road
Fort Washington, MD 20744-4988
Precision Machined Products Association
6700 West Snowville Road
Brecksville, OH 44141-3292
For useful resources about careers and internships in the metal-forming industry, contact
Precision Metal-forming Association Educational Foundation
6363 Oak Tree Boulevard
Independence, OH 4413 1-2500
Visit the Careers in Manufacturing section of the TMA’s Web site for more information on careers, wages, and educational recommendations.
Tooling and Manufacturing Association (TMA)
1177 South Dee Road
Park Ridge, IL 60068-4379