Modern clocks and watches are mass-produced on a very large scale. The material most commonly employed is known as 'clock brass'; a typical grade of clock brass usually contains 1.5 to 2 percent of lead and about 59 per cent copper, the remainder being zinc. This alloy has long been the standard material for most of the working parts of clocks, timepieces, watches and instruments possessing a clock mechanism. The flat wheels are stamped out in vast numbers from strip of the appropriate thickness, while the supporting plates, though sometimes of steel, are also often of brass. Pinion wheels are made from long lengths of extruded brass rods of similar composition which are cut off in the small pieces required for each wheel. Brass or some other copper alloy is commonly employed for engraved clock faces, as well as for screws and fittings. A very large number of the cheaper types of watches have been made in gunmetal, while others are plated nickel silver.
Until the development of suitable machine tools all clock and watch parts had to be made by hand. An expert workman made the first or master clock, which was afterwards taken to pieces and the separate parts copied as exactly as possible by less highly skilled craftsmen. Prior to about 1850 six clocks per day were considered a large output for one manufacturer. The use of power-presses and very accurate dies has so altered the rate of production that a single clock-maker can now turn out from 10,000 to 30,000 clocks and watches in a single day, and at an infinitely cheaper cost. In a normal year from 10 to 12 million clocks and watches are produced in Great Britain alone.
The hands of some of the world's most famous clocks are made either of copper or a copper alloy. The hour hands of Big Ben at Westminster are solid gunmetal, and the minute hands, which are 14 ft long, are of tubular copper. The great clock hands on the Metropolitan Life Building tower in New York have iron frames sheathed in copper; the minute hands are 17 ft long and weigh 1,000 lb each, and the hour hands are 13 ft long and weigh 700 lb each.