As one of the largest thread gage manufacturers in the United States

GSG has the thread knowledge & products to meet your needs
Back to Main Product Page
A Thread Plug GO gage checks the minimum major diameter and the minimum pitch diameter size in a part, the NOGO checks for the hole not to exceed the maximum pitch diameter size in a part. All GSG Thread Plug Gages are manufactured to ASME/ANSI B1.2 or B1.16M. All thread plug gages are made of oil hardened Tool Steel.
  • Reversible style thread plug gages are available up to and including ¾"  (19.05mm).
  • Gages can be reversed end for end in the handle resulting in double the wear life.
  • Each end of the handle is color coded, green for Go and red for Nogo.
  • Chip Grooves are provided on both ends of the Go work plug member #10/M4 and Larger. 

  • Trilock style Thread Work Plugs are available for ¾" (19.05mm) and larger. 
  • Thread Plug Gage can be reversed on the handle resulting in a longer wear life. 
  • Shown is a single end on a handle which reduces weight with large sizes.
  • Taperlock style Thread Work gages are available up to and including 1 ½ (38.1mm) 
  • Taperlocks are the most popular style in thread plug gaging. 
  • Shown is a Go and No-Go Truncated (Master) Set Plug. 
  • Set Plugs are used to set thread rings for proper fit and feel and inspect ring for wear. 
  • Set Plugs have a common pitch diameter the full thread length of the Go or No-Go section. The crest of the thread is truncated for the first half of the set plug and full form the remaining length
  • Helical Coil plug gages are used to inspect the hole prior to inserting a screw thread insert when repairing a threaded hole. 

Hole Location Plugs
  • GSG Manufactures hole location gages in two types. When checking the location of a small tapped hole the flex plug is used. 
  • When inspecting a larger hole (generally over 1.00) then the lead lock is used. Both gages locate on the flank angles of the tapped hole. 
  • Lead locks can be used in conjunction with the zero spindle and are a perfect way to inspect features for run-out to the pitch diameter of the thread. 
  • Special designs are available such as true position of threads-to-bore diameters with dial or digital indicators. 

For more information on our Threaded Plugs: