When a system has been worked out, so that any one component will assemble correctly with any mating component , both being chosen at random, the method is called interchangeable system.
Concept of Interchangeability
It is very difficult to manufacture any component or part with exact dimensions due to human inaccuracy or machine or process incapability. Thus for the components to meet functional aspect as well as to bring down the cost of production, principle of interchangeability concept is introduced. Interchangeable production means production of parts to such a degree of accuracy that will ensure an assembly which will meet the functional requirements.