Ring gages are used for go / no-go assessment compared to the specified dimensional tolerances or attributes of pins, shafts, or threaded studs.  Ring gages are used for comparative gaging as well as for checking, calibrating or setting of gages or other standards.  Individual ring gages or ring gage sets are made to variety of tolerance grades in metric and English dimensions for master, setting or working applications.  Rings are available in plain (smooth, unthreaded), threaded, cylindrical and tapered forms to go, no-go or nominal tolerances.  There are three main types of ring gages: go, no go, and master or setting ring gages.

Go ring gages provide a precision tool for production comparative gaging based on a fixed limit.  Go gages consist of a fixed limit gage with a gaging limit based on the plus or minus tolerances of the inspected part.  A go ring gage's dimensions are based on the maximum OD tolerance of the round bar or part being gaged. A go plug gage's dimensions are based on the minimum ID tolerance of the hole or part being gaged.  The go plug (ID) gage should be specified to a plus gagemakers' tolerance from the minimum part tolerance.  The go ring (OD) gage should be specified to a minus gagemakers' tolerance from the maximum part tolerance.

No-go or not-go gages provide a precision tool for production comparative gaging based on a fixed limit. No-go gages consist of a fixed limit gage with a gaging limit based on the minimum or maximum tolerances of the inspected part.  A no-go ring gage's dimensions are based on the minimum OD tolerance of the round bar or part being gaged.  The no go ring (OD) gage should be specified to a plus gagemakers' tolerance from the minimun part tolerance.

Master and setting ring gages includes gage blocks, master or setting discs, and setting rings are types of master gages used to calibrate or set micrometers, comparators, or other gaging systems.  Working gages are used in the shop for dimensional inspection and periodically checked against a master gage.