Lesson 3: How to measure with calipers

Why is a ruler insufficient for certain manufacturing tasks (tolerance)?
How do you determine which set of "jaws" to use for a specific measurement (e.g., measuring the diameter of a hole vs. the thickness of a block)?
How do you interpret the "Vernier" scale alignment to get the final decimal reading?

Calipers
Jaws
Scale
Tolerance
Vernier Scale

MAN.07.01: Demonstrate the use of precision measuring instruments and tools (specifically calipers/micrometers).
MAN.07.02: Measure parts using precision instruments to verify compliance with specifications.
MAN.08.01 (Quality Assurance): Explain the purpose of quality control and inspections.
CT-TE.9-12.4: Identify and use resources to create a product or system.

Description: This introduces the first true precision instrument.
"How to Use a Caliper" PowerPoint. Covers the anatomy of the tool (Outside Jaws, Inside Jaws, Depth Probe) and how to read the specific scale used in class (Dial or Vernier).
Students complete 3 Worksheets. Unlike the ruler worksheets, these should ideally involve measuring physical objects (or high-quality diagrams) to practice the "feel" of the tool.
Performance test on measuring specific gauge blocks or sample parts.

Purpose: To move students from "visual estimation" (rulers) to "mechanical precision" (calipers). This is a critical employability skill for quality control roles.

DOK Level:
Level 2 (Skill/Concept): Correctly placing the tool on the object (ensuring it is square/flush).
Level 3 (Strategic Thinking): Determining if a part is "within tolerance" based on the measurement obtained.

Use a fill in the blank to record readings to make sure looking at proper numbers.

Formative: Students measure an object, lock the caliper, and record the reading on 3 worksheets.

Slides: "How to Read a caliper" PowerPoint.

Handouts: 3 scaffolded practice worksheets

Tools: Physical dial caliper for every student.