Glastonbury Southern Gage Company is the largest manufacturer in the USA of thread gages (plug and ring), as well as cylindrical plug and ring gages, surveillance masters, thread wires, CMM verification gages, and optical flats. In fact, they have the largest on-the-shelf stock of thread gages. Also, their line of Centerline Flex Plug Gages allow fast and accurate inspection of threaded hole locations with your coordinate measuring machine.
Glastonbury Southern Gage was formed in 1995 when two of the largest and oldest gage companies, Glastonbury Gage and Southern Gage, were united under one owner. Glastonbury Gage was founded in 1964 in Glastonbury, CT by individuals who had trained at Pratt Whitney Machine. From these beginnings, Glastonbury Gage has continually increased its product offering and services.