Free Tool · CWI Part B
Bridge Cam Gauge Guide
The bridge cam gauge is the Swiss-army knife of Part B measurement. See what each of its functions reads and how to read it, so gauge questions on the practical exam are automatic.
Bridge cam gauge (schematic)
One gauge, several jobs — pick a measurement below to see how it's read.
Angle of preparation
- Measures
- The bevel/prep angle of the joint before welding (commonly 0–60°).
- How to read it
- Rest the gauge body on one member and swing the rotating pointer flush against the prepared face; read the angle where the pointer lines up on the scale.
- Exam tip
- Confirms the groove was prepared to the angle called for on the drawing/WPS.
Always compare the value you read to the acceptance criteria in your governing code or the exam's supplied Book of Specifications — the gauge measures, the spec decides accept or reject.
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Practice 5 Welding / CWI exam questions
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Welding / CWI · Question 1 of 5
Which welding process uses a non-consumable tungsten electrode?
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Frequently Asked Questions
What does a bridge cam gauge measure?
A bridge cam gauge is a multi-purpose weld gauge. It measures the angle of joint preparation, the height of weld reinforcement (excess weld metal), the depth of undercut or pitting, fillet weld leg length and throat, and surface misalignment between members. One tool covers several of the most common Part B measurements.
How do you measure undercut with a bridge cam gauge?
Rest the gauge on the base metal beside the weld and lower the sliding pointer into the undercut groove at the weld toe, then read the depth on the scale. Compare that depth to the acceptance limit in your code or the exam's Book of Specifications to decide accept or reject.
What is the difference between a bridge cam gauge and a Hi-Lo gauge?
A bridge cam gauge reads external features — reinforcement, undercut, fillet size, prep angle, and external misalignment. A Hi-Lo gauge is a separate tool used specifically to measure internal misalignment (high-low) at the root of a pipe joint. On the exam, know which tool answers which measurement.
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