Pit Depth and Weld Gauges

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.

  • Jr. Tri-Gauge

    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...
    $110.00
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  • Weld Profile Gauge

    Weld Profile Gauge

    G.A.L. Gage Co. GAL-29 Weld Profile Gauge Cat # 29 Quickly & easily check your welds for proper profile Only 3.5" long by 1.5" wide when collapsed. Easy to use Fits in pocket! All Stainless Steel.
    $48.50
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  • 1 3/16 to 2" Taper Gauge

    1 3/16 to 2" Taper Gauge

    1 3/16 to 2" Taper Gauge Stainless Steel All increments permanently engraved Front side - Standard Back side - Metric   SPECIFICATIONS Max Range 2" 50mm Min Range 1-3/16" 30mm Graduations 1/64" 0.2mm
    $72.00
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  • 5/8 to 1 3/16 Taper Gauge

    5/8 to 1 3/16 Taper Gauge

    G.A.L. Gage Co. Gal-28 Taper Gauge Cat # Sub 28A Features 410 Stainless Steel Measurement Scale On side I: Inches On side II: Metric Specifications   Inches Metric Max Range 5/8" 15mm Min Range 1/32" 1.0mm Graduations 1/64" 0...
    $62.75
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  • 1/32 to 5/8 Taper Gauge

    1/32 to 5/8 Taper Gauge

    G.A.L. Gage Co. Gal-28 Taper Gauge Cat # Sub 28A Features 410 Stainless Steel Measurement Scale On side I: Inches On side II: Metric Specifications   Inches Metric Max Range 5/8" 15mm Min Range 1/32" 1.0mm Graduations 1/64" 0...
    $51.00
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  • Digital Welding Gage

    Digital Welding Gage

    G.A.L. Gauge Co. GAL-18 Digital Welding Gauge Cat # 18 Holds either the zero setting or measured value at any position for differential measurements.Warranty: One Year Digital Welding GaugeFeatures  Holds either the zero setting or...
    $98.75
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  • Pipe Pit Gage

    Pipe Pit Gage

    G.A.L. Gage Co. GAL-17 Pipe Pit Gauge Cat # 17 Range is 0 to 1/2" in 1/64" & .010 Increments; Arm Can be Locked in Place at Any Dimension; All Stainless SteelMeasurement Scale: Inch or Metric Warranty: One Year The G.A.L. Pipe Pit Gauge...
    $93.00
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  • Mini Fillet Weld Keys

    Mini Fillet Weld Keys

    G.A.L. Gauge Co. GAL-16 Mini Fillet Weld Keys Cat # 16 Mini Fillet Weld Keys All Gauges Stainless Steel Set Comes with Handy Key Chain & Pocket Pouch 11 Different Sizes in Inches with Metric Equivalent Markings – 1/8” to...
    $50.00
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  • Mini Sub Gauge

    Mini Sub Gauge

    G.A.L. Gauge Co. GAL-14 Mini Sub Socket Weld Gauge Cat # 14 Check Throat DimensionsMeasurement Scale: InchWarranty: One Year “Mini Sub” Socket Weld Gauge Features  Check Throat Dimensions Check Leg Length Checks All Pipe...
    $75.00
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  • Brief Case Type Tool Kit/Lock & Key

    Brief Case Type Tool Kit/Lock & Key

    G.A.L. Gage Co. GAL-12 Brief Case Type Large Tool Kit/Lock & Key Cat # 12 Measurement Scale: Inch or Metric   G.A.L. Gage Brief Case Type Large Tool Kit/Lock & Key CAT-12Measures: 18" X 12 1/2" X 3"Tools Included:V-WAC Gauge*,...
    $959.00
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  • AWS Tool Kit

    AWS Tool Kit

    G.A.L. Gage Co. GAL-12AWS American Welding Society (AWS) Tool Kit Cat # 12AWS / CAT12AWS Measurement Scale: Inch or Metric G.A.L. Gage American Welding Society (AWS) Tool Kit CAT-12AWS   Tools Included:0-150mm Dial Caliper, 6" Scale w/...
    $251.50
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  • Skew-T Fillet Weld Gauge with Calculator

    Skew-T Fillet Weld Gauge with Calculator

    G.A.L. Gage Co. GAL-9c Skew-T Fillet Weld Gauge with Calculator Cat # 9c Checking Angle of Vertical MemberMeasurement Scale: Inch or MetricWarranty: One Year G.A.L. Gage Skew-T Fillet Weld Gauge A handy compilation of mathematical relationships...
    $123.75
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  • 7 Piece Fillet Weld Gauge Set

    7 Piece Fillet Weld Gauge Set

    G.A.L. Gauge GAL-8a / 8c 7-Piece Fillet Weld Gauge Set (1/8" to 1") Cat # 8a / 8c 7 Piece Fillet Weld Set 1/8" to 1" Markings available on BOTH sides 8  - 7 piece - marked 1 side 8a - 7 piece marked both sides 8b - 7 piece marked one side...
    $41.75
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  • W.T.P.S. Gauge

    W.T.P.S. Gauge

    G.A.L. Gage Co. GAL-7 W.T.P.S. Gauge with Calibration Block Cat # 7 G.A.L. Gage W.T.P.S. Gauge with Calibration Block CAT-7 Measure Undercut 0.010 Deep Undercut shall be no more than 0.010 in. (0.25 mm) deep when theweld is transverse to the...
    $71.00
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  • Automatic Weld Size Weld Gauge

    Automatic Weld Size Weld Gauge

    G.A.L. Gage Co. GAL-6 Automatic Weld Size AWS Type Gauge Cat # 6 For Accurate Calibration of Butt Fillet Type WeldsMeasurement Scale: Inch or Metric Warranty: One Year G.A.L. Gage Automatic Weld Size AWS Gauge CAT-6 For Accurate Calibration of...
    $38.00
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  • V-WAC" Single Weld Gage

    V-WAC" Single Weld Gage

    G.A.L. Gauge Co. GAL-5 V-WAC Single Weld Gauge Cat # 5 / CAT5 Undercuts/Pits to 1/4 Inch, Crowns to 1/4 Inch by 1/64 Inch Increments (Tolerance .006") Measurement Scale: Inch Warranty: One Year GAL Gage V-WAC Single Weld Gauge...
    $43.25
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  • Pocket Bridgecam

    Pocket Bridgecam

    G.A.L. Gage Co. GAL-4a Pocket Bridge Cam Gauge Cat # 4a Check Angle of Preparation, Excess Weld Metal, Depth of Undercut, Depth of Pitting, and more. Measurement Scale: Inch & Metric Warranty: One Year G.A.L. Gauge Co. GAL-4 Bridge Cam Gauge...
    $157.00
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  • Bridgecam Gauge

    Bridgecam Gauge

    G.A.L. Gauge Co. GAL-4 Bridge Cam Gauge Cat # 4 Measurement Scale: Inch and Metric Excess Weld Metal (capping size) Warranty: One Year G.A.L. Gauge Co. GAL-4 Bridge Cam Gauge Cat # 4 The following measurements are possible in either inches or...
    $140.75
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  • G.A.L. Adjustable Fillet Weld

    G.A.L. Adjustable Fillet Weld

    G.A.L. Gage Co. GAL-3 Adjustable Fillet Weld Gauge Cat # 3 G.A.L. Gage Adjustable Fillet Weld Gauge CAT-3 Unequal leg measurement feature G.A.L. Adjustable Fillet Weld Gauge is easy to use Features  Measure Fillet Weld Measure Weld Throat...
    $100.50
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  • "HI-LO" Welding Gauge Stainless

    "HI-LO" Welding Gauge Stainless

      The G.A.L. Gage Co. GAL-1 HI-LO Welding Gauge Cat # 1 is a multipurpose and versatile gauge. As with many of our gauges, both standard and metric units of measurement are available directly on the gauge for dimensional verification...
    $138.50
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  • FERRITSCOPE® FMP30 (US SALE ONLY)

    FERRITSCOPE® FMP30 (US SALE ONLY)

    FERRITSCOPE® FMP30 - FOR SALE IN THE US ONLY Part No.: FERRITSCOPE® FMP30 Measurement of the ferrite content in: Duplex steel, Austenitic steel welds (tubes, sheets), Normal steel with austenitic chrome alloy steel welded cladding (boilers,...
  • Tri-Weld Gauge

    Tri-Weld Gauge

    The Tri-Weld Gauge provides easy to read measurements of the following welding and fit-up parameters; Internal Hi-Lo, Gap, Filet Height and Leg Length, Weld Height, Undercut Depth, Misalignment, and Angle of Preparation. The Tri-Weld Gauge is equipped...
    $325.00
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  • Junior Tri-Gauge VM

    Junior Tri-Gauge VM

    Junior Tri-Gauge VM® Lever Type Pit & Welding Gauge Part No. N88L-2 Mechanical Lever Pit Gauge with Metric and Imperial Scales Range/Resolution: +/- 3mm (0.100") / 0.2mm (0.005")   The Junior Tri-Gauge VM® Lever Type Pit Gauge...
    $110.00
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