Plug, Pin and Ring Gages

Plug, Pin and Ring Gages

Plug gages are precision ground cylindrical measuring devices. Plug gages are often used in go-no go gauges to evaluate hole diameters. These are available in a variety of classes, such as Class ZZ, Z, X, and XX.

Example tolerances for a 1 inch diameter are as follows:

Tolerance ClassTolerance (For a 1.00 inch cylinder)
Example Tolerances for 1 inch Diameter Ring or Plug Gage

Tolerances can be unilateral to either the plus or minus side, or they may be bilateral, split 50/50 between plus and minus side (as with master gages).

For example, a NoGo ring gage would have a unilateral tolerance toward the plus side.

See these standards:

  • ASME B89.1.5 – 1998(R2019) Measurement of Plain External Diameters for use as Master Discs or Cylindrical Plug Gages
  • ASME B47.1 -1988 (R2007) Gage Blanks