Covers rings for setting instruments used for precision measurement of internal diameters by two-point or three-point contact methods, in a range of diameters from 0.08 in. to 6 in. It establishes a series of blank sizes; defines material, its heat treatment and hardness; and specifies requirements for working surface with respect to finish and accuracy. Three grades of accuracy are provided for. For metric series rings see AS 1001.
