§4.2A · Under Inspector duties
Which weld gauge reads which dimension on the CWI?
Fillet weld gauge, bridge cam, V-WAC, hi-lo, pit depth: each one reads a dimension or two on a weld, and the CWI expects you to match the measurement to the tool before you read a number. On structural work, where fillets are everywhere, the fillet weld gauge is the one you'll reach for most. How size and throat relate is on fillet size vs throat.
- Exam
- CWI
- Clause
- §4.2A
- Tags here
- 9
- Parent
- Inspector duties
4.2A.1Gauges on Part A and Part B
Part A asks about the tools. Part B hands them to you. AWS supplies an inspection tool kit at the Part B site, together with the Book of Specifications, an exhibits booklet and a set of plastic weld replicas, and you judge what you measure against acceptance criteria (AWS CWI Examination User Guide, September 2026, checked October 2026). The replica set and the exhibits booklet are confidential, so nobody can legitimately show you them ahead of time. The Part B practical page covers the format.
Timing matters as much as the tool. B5.1:2025 has inspectors build visual inspection procedures around before, during and after welding (AWS B5.1:2025, Table 5.1, checked October 2026). On the floor that means fit-up, joint prep and preheat before the arc is struck, interpass temperature during, and size and profile after. A hi-lo reading taken after the root pass is a record of a problem. Taken at fit-up, it's a chance to fix one.
Gauges are visual tools. They measure what's on the surface: size, profile, reinforcement, toe condition, fit-up. Anything below the surface belongs to NDE. The visual examination clause is the parent topic. Under B5.1:2025, welding inspection and discontinuities make up at least 34% of Part B (AWS B5.1:2025, Table 8.1, checked October 2026).
4.2A.2Which gauge reads what
| Tool | Reads | Where it sits | Watch for |
|---|---|---|---|
| Fillet weld gauge (blade set) | Fillet leg size; throat on a concave face | Blade against both members, tip on the face | Convex face: check the leg. Concave face: check the throat |
| Bridge cam gauge | Reinforcement height, undercut depth, fillet leg and throat, bevel angle, misalignment | Bridge on the plate, cam pointer down to the feature | It carries several scales; read the one you set it for |
| V-WAC gauge | Undercut depth, reinforcement, pore size by comparison | Flat on the plate beside the weld | Read undercut at its deepest point along the toe |
| Hi-lo gauge | Mismatch between members, especially pipe bore alignment | Across the joint at fit-up | Measure before the root pass, when it can still be fixed |
| Pit depth gauge | Depth of pits, gouges, undercut | Base on the surface, plunger down | Zero it on flat stock first |
| Bevel protractor | Bevel angle of the prep | Blade along the bevel face | On a V, the groove angle is both bevels together |
| Temperature crayons or contact thermometer | Preheat and interpass temperature | On the base metal, the distance from the joint the code sets | Read the base metal, away from the bead |
Scales and ranges differ by maker. Check the markings on the gauge in your hand before you read it.
4.2A.3Taking a reading you can defend
Clean the spot
Slag, spatter and loose scale under the gauge base lift it off the plate, and every reading after that is off.
Check zero
Close the gauge on flat stock. If the pointer doesn't sit on zero, note the offset or use another gauge.
Set on the right reference
Base metal for reinforcement and undercut. Both members for a fillet leg. The prep face for a bevel.
Find the worst spot
Run the gauge along the weld. The reading that counts is the deepest or highest point you find, not the first one.
Record it so it can be found
Distance from a marked datum, the length affected, and the value. A number with no location is no use to the repair crew.
Compare against the criteria in front of you
On Part B that's the Book of Specifications. On the job it's the contract code. Undercut vs overlap shows why the name matters before the number.
4.2A.4Tool for the job
Match the measurement to the tool, then read the remarks for why the other tools don't fit.
0 of 9 tagged · 0 accepted
Tag 01
Which tool is most appropriate for measuring weld reinforcement height?
Remarks on every option
- A A fillet gauge checks fillet leg size and contour, not groove reinforcement height.
- B A tape is for lengths. It can't read a small height off a curved weld face.
- C Correct: A bridge cam gauge rests on the plate and reads how high the weld face stands above it.
- D A pit depth gauge reads down into a pit or undercut, not weld metal standing above the plate.
Pick an option. The remarks on all 4 open here.
Tag 02
Which multi-purpose weld gauge has a pointer made for reading undercut depth?
Remarks on every option
- A A protractor reads angles, such as bevel or groove angle. It can't reach into a toe groove for depth.
- B A plain depth gauge can read a pit or groove, but it's a single-purpose tool, not a multi-purpose weld gauge.
- C Correct: The V-WAC gauge has a pointer for undercut depth and also reads reinforcement height and helps size porosity.
- D A ruler measures lengths along the surface. It can't give you a reliable depth at the toe.
Pick an option. The remarks on all 4 open here.
Tag 03
What type of gauge is used to measure both leg lengths and throat thickness of a fillet weld?
Remarks on every option
- A Correct: One gauge set covers both checks: the leg blade for size on any profile, and the throat blade when the face is concave and the throat governs.
- B A hi-lo gauge measures mismatch and internal alignment on pipe and plate joints, not fillet legs.
- C A pit depth gauge measures the depth of pits and undercut, not leg length.
- D A bevel protractor measures angles like a groove bevel, not fillet legs or throat.
Pick an option. The remarks on all 4 open here.
Tag 04
Which tool is most appropriate for measuring the angle of a groove weld preparation?
Remarks on every option
- A A rule measures lengths and root opening, not angles.
- B Correct: A bevel protractor reads the bevel angle directly. Add both bevels to get the groove's included angle.
- C A fillet gauge checks fillet size. It isn't made for groove prep angles.
- D A pit depth gauge reads depth, not angles.
Pick an option. The remarks on all 4 open here.
Tag 05
Which tool is most appropriate for measuring the depth of surface irregularities?
Remarks on every option
- A A fillet gauge checks fillet size and contour, not how deep a pit goes.
- B A rule can't read small depths with any accuracy.
- C A protractor measures angles, not depth.
- D Correct: A pit depth gauge sets its base on the surface and reads how far down a pit, gouge or undercut goes.
Pick an option. The remarks on all 4 open here.
Tag 06
What is the primary purpose of using a weld gauge during visual inspection?
Remarks on every option
- A Temperature gets checked with temp sticks or a contact thermometer, not a weld gauge.
- B Hardness takes a hardness tester. Bead shape tells you nothing about it.
- C Correct: Weld gauges measure what you can see (leg size, reinforcement, undercut, concavity, convexity) against the drawing and code.
- D Internal flaws need RT or UT. A gauge only reads the surface.
Pick an option. The remarks on all 4 open here.
Tag 07
On a pipeline job, which equipment is the basic kit for direct visual inspection of the welds?
Remarks on every option
- A Temperature indicators are for preheat and interpass checks, not for looking at the weld.
- B Correct: A flashlight and an inspection mirror are the basic visual kit: light on the weld and a view into hard-to-see spots.
- C An ultrasonic unit is UT, a separate NDE method, not visual.
- D Penetrant is PT, a separate NDE method with its own procedure.
Pick an option. The remarks on all 4 open here.
Tag 08
When is a magnifying glass required for visual weld inspection?
Remarks on every option
- A Most visual is done by eye. The magnifier comes out when you need a closer look, not on every weld.
- B Correct: Low-power magnification helps confirm fine indications, like a suspected crack tip or fine porosity, that are hard to judge by eye.
- C Thickness doesn't decide it. Magnification is for small surface features; deeper flaws need other NDE.
- D Heat isn't the reason. A magnifier helps you see small things, not keep your distance.
Pick an option. The remarks on all 4 open here.
Tag 09
How should joint mismatch be measured in a butt weld?
Remarks on every option
- A The length of the mismatched stretch may get noted, but mismatch itself is the offset.
- B Weld width isn't mismatch. Mismatch is how far one surface sits above the other.
- C Groove depth is a joint-prep dimension, not mismatch.
- D Correct: Mismatch (hi-lo) is the offset between the two members' surfaces. Measure it with a hi-lo or similar gauge and check it against the allowed limit.
Pick an option. The remarks on all 4 open here.
Ten questions on a break
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