Precision Measurement — Identify the Instrument That Measures OD, ID, Thickness, and Depth Which single versatile instrument is commonly used on the shop floor to measure external and internal diameters, thicknesses of parts, and the depth of holes or slots?

Introduction / Context:
Dimensional inspection in machining and fabrication relies on selecting the appropriate instrument for the feature being measured. A commonly used, multipurpose tool is expected to handle OD, ID, thickness, and depth with adequate resolution for general work.

Given Data / Assumptions:

• Shop-floor measurements (not laboratory metrology).
• Need to measure a variety of geometries with one tool.
• Resolution requirements typically 0.02 mm (vernier) or 0.01 mm (digital) level.

Concept / Approach:
A vernier caliper includes outside jaws (OD/thickness), inside jaws (ID), and a depth rod (holes/slots). Specialized micrometers offer higher accuracy but are limited to a single function (outside, inside, or depth). Therefore, for versatility in one instrument, the vernier caliper is the correct choice.

Step-by-Step Solution:
Identify features to be measured: OD, ID, thickness, depth.Map instruments to features: only vernier caliper has all required contact elements.Conclude: vernier caliper best satisfies the multi-feature requirement.

Verification / Alternative check:
Most basic metrology kits include a vernier (or digital) caliper as the first-line universal gauge for mixed features.

Why Other Options Are Wrong:
Outside/inside micrometers measure only one type each; depth micrometer measures only depth.Dial indicator requires fixtures and does comparative checks, not absolute dimensions across all features.

Common Pitfalls:
Using a caliper beyond its accuracy class where a micrometer is required for tight tolerances.

Final Answer:
vernier caliper