In modern usage, a millwright is a craftsman or tradesman engaged with the erection of machinery. This includes such tasks as leveling, aligning and installing machinery on foundations or base plates and setting, leveling and aligning electric motors or other power sources such as turbines with the equipment, which millwrights typically connect with some type of coupling. The exact duties of a millwright vary depending on whether they are unionized or not, with union rules typically being more restrictive than non-union situations, which may have their own job description. Related but distinctly different crafts include machinists and mechanics.
Historically, millwrights built watermills and windmills, mostly of wood with a limited number of metal parts. More generally in the English speaking world, early millwrights were specialist carpenters who erected machines used in agriculture, food processing and processing lumber and paper. In the early part of the Industrial Revolution, their skills were pressed into service building the earliest powered textile mills.
Modern millwrights work with steel and other materials and must often combine the skills of other mechanical trades in order to successfully install industrial machinery or to assemble machines from pre-fabricated parts. Modern millwrights must also be able to read blueprints and other schematics to aid them in the construction of complex systems. Millwrights are frequently unionized, with estimated numbers of around 45% in the US.
A millwright originally was a specialized carpenter who had working knowledge of driveshafts, bearings, gearing and mechanical belts . The "mill" in millwright refers to the genesis of the trade in building flour mills, sawmills, paper mills and fulling mills powered by water or wind.
Oliver Evans was a prominent American millwright who published a manual for millwrights.
A millwright today is someone who maintains, repairs or constructs industrial machinery for assembly lines, pumping stations and other utilities, print shops, steel mills, oil refineries, assembly plants, mining, power stations,saw mills, pulp mills and other industries employing fixed heavy machinery.
Millwrights are usually responsible for the unassembled equipment when it arrives at the job site. Using hoisting and moving equipment, they position the pieces that need to be assembled. Their job requires a thorough knowledge of the load-bearing capabilities of the equipment they use as well as an understanding of blueprints and technical instructions.
Millwrights must be able to read blueprints and schematic drawings to determine work procedures, to construct foundations for and to assemble, dismantle and overhaul machinery and equipment, using hand and power tools and to direct workers engaged in such endeavors. The use of lathes, milling machines and grinders may be required to make customized parts or repairs. In the course of work, millwrights are required to move, assemble and install machinery and equipment such as shafting, precision bearings, gear boxes, motors, mechanical clutches, conveyors, and tram rails, using hoists, pulleys, dollies, rollers, and trucks.
Millwrights are also involved in routine tasks, such as lubrication of machinery, bearing replacement, seal replacement, cleaning of parts during an overhaul and preventative maintenance.
Millwrights also must have a good understanding of fluid mechanics (hydraulics and pneumatics), and all of the components involved in these processes, such as valves, cylinders, pumps and compressors.
Modern standards of practice for millwrights also require working within precise limits or standards of accuracy, at heights without fear; the use of logical step-by-step procedures in work; planning, solving problems and decision-making based on quantifiable information.
Millwrights are trained to work with a wide array of precision tools, such as vernier calipers, micrometers, dial indicators, levels, gauge blocks, and optical and laser alignment tooling.
A typical job description for an industrial maintenance mechanic (millwright) often includes the primary purposes of installing, maintaining, upgrading and fabricating machinery and equipment according to layout plans, blueprints, and other drawings in industrial establishment.
Millwrights by nature of their profession have to be extremely well versed in many aspects of construction/demobilization. They may install a conveyor system at an airport one week and the following week work at an Industrial wastewater treatment plant.
Millwrights in the power generation industry assemble, set, align and balance turbines/rotors. Millwrights also perform critical lifts involving major components to be flown level at up to and within .005” (5 thousandths of an inch). Because of their training and expertise, Millwrights are generally chosen to work on tasks associated with flying and setting heavy machinery.
Millwrights are also in demand as teachers for vocational programs, both at the high school level and in post-secondary institutions. Many high schools feature fabrication courses that include metal work, where the experience of a qualified millwright is valuable. Often, these millwrights are paid a premium based on their years of field experience.
Most millwrights are educated through apprenticeship programs where they receive a combination of classroom education along with a good deal of on-the-job training. Most programs last about four years, and may include college degrees. Apprentices are usually paid a percentage of the average millwright's wage, and this percentage increases with experience.
Training courses received by a Union Millwright: