STI Screw Thread Insert Gages (Working Thread Plug)

STI Screw Thread Insert Working Thread Plug Gages
STI Screw Thread Insert Working Thread Plug Gages

Working thread plug gages are used to insure the threaded hole complies to specification, normally either a 2B or 3B classification. In the case of Screw Thread Insert (STI) gages the the thread designation refers to the insert thread so the size of the gage for the tapped hole is larger than the nominal size.

  • Working thread plug and ring gages are furnished with Standard class “X” industry tolerance
  • For rings with class “W” tolerance pitch diameters, set plugs must be ordered or provided
  • Set plugs are truncated and have class “W” tolerances on lead and class “X” tolerances on the pitch diameter