BS 969:2008 PDF

1   Scope This British Standard specifies tolerances and limits for simple forms of limit gauges, such as cylindrical plain plug, ring and gap gauges, for which gauge limits have not been stipulated. It specifies gauge tolerances for workpiece tolerances in the range between 0.009 mm and 3.200 mm and how gauge limits are related to the workpiece limits. It also specifies types of gauge according to size and minimum workpiece tolerance.

NOTE Where a workpiece tolerance is outside the range 0.009 mm to 3.200 mm, or if it is not possible to conform to Table 2 regarding type of gauge, gauge tolerance and workpiece size, direct measurement should be used.

The gauge tolerances specified are such that the size of any workpiece accepted by a gauge lies within the boundaries constituted by the workpiece limits. Furthermore, the magnitude of the gauge tolerances is consequent upon the amount of the workpiece tolerance only. A wear allowance is provided on all GO gauges, i.e. those that control the maximum material condition of the workpiece.