Setting Masters – Ring Gages, Plug Gages & Set Discs

A master is a calibrated reference standard used to zero or calibrate the gaging system.  It is a physical object, like a plug, ring, or disc, with a precisely known size that acts as a reference point for measuring the dimensions of workpieces.

Master Rings are used to set air probes and other types of bore gages to a known size.

Master Plugs are used with air rings and other external diameter measuring instruments as setting standards. Depending on whether single or dual masters are required, single or double-ended aluminum handles are utilized.

Master Discs are used for the same purpose as master plugs, except that these members incorporate plastic grips on each end, rather than aluminum handles.