1 Scope
1.1 This British Standard relates to plain setting rings primarily intended to be used,
either singly or in combination, for checking the scales on internal diameter measuring
equipment.
It provides for a range of metric rings in sizes from 2 mm to 150 mm in three grades
of accuracy, viz.
NOTE Sizes below 2 mm are not included because it is impracticable to measure them.
Requirements are specified for material, hardness and surface texture and recommended
sections for the setting rings covered by this standard are included in an appendix.