Metric Conduit Series – Screw Plug Gauges

S.G. Prittie manufactures a range of screw plug gauges to suit electrical conduit fittings. Gauges feature 1.5mm pitch and class 6H. Most standard sizes such as M16, M20, M30, M40, M50 and M63 are in stock and we also manufacture larger sizes to order. All of our gauges are made from hardened tool steel to ensure long life and supplied with manufacturers certificate of conformance. (COC)

Product options

NATA Calibration – ISO 17025
Storage case for a single gauge or for a gauge set

Applicable standards


Why this product is used

Screw plug gauges are an efficient way to check internal thread conformance. Simply check that the Go gauge will engage the part to full depth and that the Nogo gauge will not enter. This condition indicates a conforming part.

  • Customisation

    Customisation is offered on most gauges. We can add a new feature to a standard gauge, manufacture a revised design based on a standard gauge, or design a new gauge to suit your application.

  • Support

    We offer design and technical support for all our gauges, as well as support for measurement and calibration inquiries. Contact us via phone or email.

  • Delivery

    We offer express or economy delivery and can send products to local, interstate and overseas locations. We’re also happy to use your own delivery supplier.

  • Manufacturing

    We are an Australian business located in Airport West Victoria. Quality is a priority and we have ISO 9001 and ISO 17025 management systems in place.


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Thread type Range in stock Range manufactured
ISO Metric 1.5 mm Pitch Class 6H M16 – M63 M16 – M90


How often do I need to calibrate my gauge?

There is no fixed time, calibration frequency is based on how often the gauge is used and the conditions that the gauge is exposed to. Frequent use and abrasive materials will require more frequent calibration, low use in a clean environment will allow less frequent calibration. Usually the user determines the calibration frequency.

Can the Nogo gauge enter the part?

Generally no, but a limited entry is permissible in some cases, see download sheet for details.

If you need assistance selecting the correct gauge or have technical questions please contact us.

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