"Purpose: This information report provides guidance when the ISO International metric tolerance system for limits and fits per ISO/R286 or ANSI B4.2-1978 is applied on a standard@ and also provides a selected series of limits and fits for powerplant construction suitable for holes and shafts up to 500 mm. For holes or shafts over 500 mm or for limits and fits not shown@ ISO/R286 should be consulted. Application: The selected series of limits and fits included in this report are recommended for use whenever a graded series of tolerances are required. This applies whether the design feature is a fit or not. Application of only a limited number of the limits and fits in a design will assist in reducing production costs by confining hole and shaft sizes to a standard set of limits and therefore reducing the number of gauges needed. It also allows the production and quality control area to make greater use of ""go"" and ""not-go"" gauges even for small production runs of parts. For the sake of simplicity the system refers to holes and shafts@ however this does not limit its use. The system can be applied equally well when specifying limits and fits for lungs@ slots@ parallel surface and tangent planes."