spare parts

previously manufactured machine components and subassemblies, designed for replacement of parts that have worn out through use, particularly the rapidly wearing pieces such as bushings, ball bearings, gears, and pistons. Spare parts are generally produced with the same dimensions as original parts or in sizes which take into consideration wear of mated components. Lists and rates of consumption of spare parts for planned repairs are established in each industry. Such lists and rates should ensure uninterrupted service of machinery during operation, reduce the machine idle time connected with repair, and lower the cost of repair operations.