Vermont Trilock

Trilok (Trilock) Plug GagesTrilok plug gages use a three-point (trilock) bolting system to attach the gage member to the handle, providing stability for heavier or larger gages. Like reversible types, they are reversible—when one end wears, the member can be turned around and re-bolted, doubling the gaging life. This style is suited for robust inspections where weight and size could make other designs impractical. They come in tolerances like Class XX, X, Y, or Z, primarily in steel, with options for Go (plus), No-Go (minus), or master (bilateral) tolerances.

Handles are designed with bolt holes for the trilock mechanism, often larger and more durable to handle the weight. Custom markings are available. Size ranges focus on larger diameters, starting from 0.7601" to 3.5100" or higher (up to 6.0100" in some catalogs; 19.300mm to 89.150mm), making them unsuitable for very small gages.