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    • Pit Depth and Weld Gauges

    • Tri-Gauge

      Tri-Gauge

      The Tri-Gauge is today's most versatile Lever Pit Gauge, with its Metric and dual Imperial Scales. Additionally, the Tri-Gauge serves as a basic Weld Inspection Gauge for; Undercut Depth, Weld Crown Height, a Porosity (diameter)...

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    What is a Pit Gauge?

    A basic pit gauge has a simple lever and a pointer, whereas advanced and more accurate models may have digital readouts or analog dial indicators. Different sizes and designs of pit gauges enable corrosion inspectors to measure components of all shapes and sizes in almost all industries.

    Various surface shapes and sizes require different types of pit gauges. Some bigger shapes like tanks, have gauges with parts that can be extended to cover larger surface areas. The type of tip that scans the pit varies in length and thickness, and the most common are:

    • Standard - Universal for general corrosion tests
    • Conical - Larger than standard, used when a large amount of scanning is required
    • Needle tip - For small diameter and shallow pits (very delicate)

    A pit gauge is very convenient to use, as it is composed of only one movable part and precisely registers to +/- 0.0005 inches. The scale of a pit gauge is graduated in decimal and fractional inches and is capable of measuring degree of thickness from 0 to 0.625 inches. Pit gauges are available in pocket sizes, so they can be easily carried and transported.

    The following equipment particularly benefits from corrosion measurement using pit gauges:

    • Pressurized equipment (boilers, pipelines, storage tanks, piping, vessels)
    • Tube-shaped products (drill pipes, casings)
    • Aircraft elements
    • Structures and bridges

    Pit gauges are used to determine whether corrosion has increased. In actual settings, inspectors are continually required to conduct measurements of pit depths.

    Lever Pit Gauges

    Lever Pit Gauges are the simplest form of Pit Gauge, with an original Patent issued in 1935 as a Pipe Pit Gauge (J.C. Stirling). Until Western introduced the Tri-Gauge in 2004, no changes had been made to the original design of Stirling's. Western's improved designs make our Pointer Type Pit Gauges effective for Weld Measurement Gauges for Weld Undercut and Weld Reinforcement.

    Western offers the original Tri-Gauge, which has a range of +/-25mm (0.50") with a resolution of +/-0.5mm (0.01") and the new Jr. Tri-Gauge (introduced in 2012) has a Range of 3mm (0.100"), with a resolution of 0.2mm (0.005").

    What is a Tri-Gauge?

    The Tri-Gauge® is today’s most versatile Lever Pit Gauge, with its Metric and dual Imperial Scales. Additionally, the Tri-Gauge® serves as a basic Weld Inspection Gauge for; Undercut Depth, Weld Crown Height, a Porosity (diameter) Comparator; and both Metric and Imperial Rules. The Tri-Gauge® is fitted with a Patented pointer Offset Correction® for improved accuracy and repeatability. Lever Pit Gauges are intended to evaluate corrosion, and not as an absolute measuring tool. The Tri-Gauge® is supplied with a Pocket Protector type Case and Instructions

    What is a Jr. Tri-Gauge?

    The Junior Tri-Gauge VM® is today’s most accurate Lever Pit Gauge, with a continuing tradition of Metric and Dual Imperial Scales. The Junior Tri-Gauge® serves its traditional use as a Pit Depth Gauge, but also as a Weld Inspection Gauge for: Weld Undercut Depth, Weld Crown Height, and both Metric and Imperial Rules. The Junior Tri-Gauge®, like the original Tri-Gauge®, is fitted with our Contact Point Offset Correction® for improved accuracy and repeatability. Any Lever Pit Gauge is intended to evaluate corrosion / erosion and is not an absolute measuring tool. The Junior Tri-Gauge® is supplied with a Vinyl Sheath Storage Case and Instructions.

    What standard Pit Gauges does MTest offer?

    Over the years, the popularity of our various models has evolved, due to market acceptance and knowledge of the capabilities of our Pit Gauges. Many years ago, the Basic Pit Gauge was popular, simply because of price, and the shape was similar to Starrett's Machinist Depth Gauges. The Starrett Gauges were not specifically designed for Pit Gauging, due to the large size, heavy weight, and the extremely limited measurement range. Another example of a misapplied to is the use of a Tire Tread Gauge for corrosion.

    Today, our versatile Pocket Pit Gauge is, by far, our most popular Pit Gauge model, due to its ability to be used on flat and simple or complex curvatures. Pipe, Tube, and Vessels are examples of Simple Curvatures, while some examples of Complex Curvatures are Cylinder Necks (and Bases), the Knuckle area of Vessel Heads, Pump Impellers, and Turbine Blades.

    The models that have gained popularity over the years and are currently even in production with the Basic Pit Gauge, are our Reaching Pit Gauges. Reaching Pit Gauges have a huge advantage over conventional 'Center Mount' Pit Gauges in that measurements can be taken right next to a weld, reinforcing pad or risers.