What gauge is used to measure undercut?

What gauge is used to measure undercut?

• A. Cam Gauge
• B. Dial Gauge
• C. Feeler Gauge
• D. Vernier Caliper

Answer: (A)

Undercut is a down-right groove that forms along the weld toe, creating a recess in the base metal beside the weld. To assess how deep that recess is, you need a tool that can follow the groove’s profile and translate that depth into a readable value. A cam gauge is designed for this purpose: its cam-shaped contact sits in the undercut and, when the gauge is set against the surrounding surface, the reading reflects the depth of that undercut. This makes it specifically suited to measuring undercut quickly and consistently. Other tools measure different things. A dial gauge records tiny linear displacements but isn’t built to capture a groove depth in a weld toe. A feeler gauge uses thin blades to check gaps, which can be manual and imprecise for a curved recess. A Vernier caliper can measure external, internal dimensions, and depth, but it isn’t as well suited for directly reading the depth of an undercut along a weld toe.

Undercut is a down-right groove that forms along the weld toe, creating a recess in the base metal beside the weld. To assess how deep that recess is, you need a tool that can follow the groove’s profile and translate that depth into a readable value. A cam gauge is designed for this purpose: its cam-shaped contact sits in the undercut and, when the gauge is set against the surrounding surface, the reading reflects the depth of that undercut. This makes it specifically suited to measuring undercut quickly and consistently.

Other tools measure different things. A dial gauge records tiny linear displacements but isn’t built to capture a groove depth in a weld toe. A feeler gauge uses thin blades to check gaps, which can be manual and imprecise for a curved recess. A Vernier caliper can measure external, internal dimensions, and depth, but it isn’t as well suited for directly reading the depth of an undercut along a weld toe.