Screw Plug and Ring Gauges

Normal Style

A Single-ended "Go” Gauge for checking the "lower limit” of threaded holes and checks the full form thread.


Style E Plug Gauge

A Double-ended Limit Gauge which is, in effect, a combination of a normal Single-ended "Go” Gauge for checking form thread, and a Style ‘D’ "Not Go” Effective Plug Gauge. We supply a range of plug gauges across the UK.

Style G Plug Gauge

A Double-ended Limit Gauge as Style ‘F’, but with a plain cylindrical Minor Diameter Gauge made to the "Go” dimensions for checking the "low limits” of the component Minor Diameter and threaded holes. Complete with taper screw at either end.


Style A Setting Plug Gauge

A Double-ended Plug Gauge for setting Adjustable Thread Caliper Gauges. Both ends are truncated on the Major Diameter and cleared on Minor Diameter to ensure that the anvils of the Caliper Gauges are accurately set to the Effective Diameter.



Style D Plug Gauge

A Single-ended "Not Go” Gauges for checking the high limits of threaded holes. This gauge checks the EFFECTIVE Diameter only and is made in accordance with customer’s requirements. 


Style F Plug Gauge

A Double-ended Limit Gauge, the "Go” end of which has a normal "Full Form” thread, whilst the other end is a plain cylindrical "Not Go” Gauge for checking the "high limits” of the Minor Diameter of the compound.


Style H Plug Gauge

A Double-ended Limit Gauge combining "Not Go” Effective Style "D” plug Gauge and a "Not Go” Minor Diameter Gauge.


Solid Screw Ring


These screw ring gauges are manufactured to the latest international standards. Available in a range of tapered sizes and in various classes of external threads, these screw ring gauges are made of high quality materials.



Gauges above 2 1/2” are made to trilock design as illustrated. They are normally supplied as Single-ended Gauges and therefore as Style ‘E’ Plug Gauge comprises a pair of gauges, a Single-end "Go” and a Single-end "Not Go”.

When ordering gauges please state which of the above types are required, as we stock a range of plug gauges, tapered gauges, screw rings, and more. Also specify the class of thread fit the gauges are required to check. 

In I.S.O. Metric threads the various classes of internal thread are 4H, 5H, 6H and 7H.

In I.S.O. Metric threads the various classes of external thread are 4h, 6g and 8g.

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About Mercury

Mercury Tool & Gauge offer an extensive range of products that are manufactured to meet the most demanding quality needs in today's market.


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    02476- 694 -030
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    221 Torrington Avenue
    CV4 9HN

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