Hex Plug Gages

Thread Check Inc. supplies a complete range of Hex Plug Gages per ANSI B18.3 and ANSI/ASME B107.17M. Hex plug gauges per ASME B107.17M are used to inspect wrench opening and spark plug wrench opening for inch and metric sizes. Hex plug gauge sizes range in inches covers 1/8 to 3.0” and 2.0mm to 75mm in metric. The standard covers hex plug gage designs and square gage designs. Hex plug gauges per ASME B18.3 covers dimensional data for various types of hexagon and spline socket cap screws, shoulder screws, set screws, and hexagon and spline keys recognized as the American Standard. Thread Check supplies ASME B18.3 gages in fractional sizes from .028” to 1.00” and metric sizes from .70mm to 24.00mm. Hex plug gauges are manufactured from oil hardened tool steel with a minimum HRC of 60 HRC. Thread Check Inc. can also build custom hex plug gauges per customer specifications. Custom gages include extra lengths, extensions, alternative materials and tighter tolerances.

To gage hexagon sockets that are not chamfered per ASME B18.3, the go member of the gage should enter freely to the minimum key engagement depth specified in the standard. The no go gage member should not enter any of the 3 across flat dimensions of the socket for nominal socket sizes of 1/8 in. and larger and the no go member should not enter the socket for nominal socket sizes smaller than 1/8 in. For hexagon sockets that are chamfered, the no go gage member is permitted to enter only to a depth of 10% of the nominal socket sizes up to and including 1/16 inch, and 7.5% of the nominal socket sizes for larger sockets.

To gage spline sockets per ASME B18.3, the go member gage should enter easily to the minimum key engagement depth specified in the dimensional standards of the tables. The no go gage member should not enter the spline sockets that are not chamfered. For spline sockets that are chamfered, the no go gage member is allowed to enter up to a depth equivalent to 10% of the nominal socket size for sizes up to and including .060 inches and to 7.5% of the nominal socket for larger sockets.