Plug gages are manufactured in three basic AGD styles. Wire type, also known as pin gages, taper lock and trilock. These styles offer a choice of wire type or taper lock gages in small range, taper lock or trilock gages in the middle range and trilock in the larger gage sizes. Special plug gage for a variety of special applications can be furnished. These special plug gages include extra-long or short plugs, progressive, concentricity, alignment and combination diameter and depth plug gages.
Pin gages are wire type plug gages. Pin gages may be extended from the handle a specific amount as desired or reversed to increase the life of the gage. Because of the great saving in cost per hole gaged, pin gages are almost universally used for gaging holes below .5" diameter.
Thread gauges are made for gaging of internal or external threaded surfaces. Typical thread gauge applications are gaging of the bores of the nut and the outside thread on screws or bolts. Thread gauges are available in "Go" and "No-go" sizes, conforming respectively to the maximum or minimum material limits of the measured part.