Lesson 3: Measure Twice, Draft Once: Using Calipers
Duration of Days: 3
Lesson Objective
Students will use dial or digital calipers to measure physical objects to the nearest thousandth of an inch.
Why is a ruler insufficient for precision manufacturing?
What is "tolerance," and why does measurement accuracy matter in a machine shop?
Caliper, Inside Diameter (ID), Outside Diameter (OD), Depth Probe, Tolerance.
CT CADD.02.03: Demonstrate proficiency in measuring with precision instruments.
Students rotate through stations measuring various mechanical parts (bolts, washers, PVC pipes) using calipers and recording their data in a log.
Purpose: To transition from "nominal" measurements to "actual" precision measurements.
DOK Level: 2 (Skill/Concept).
Provide digital calipers for students who struggle with reading dial gradients; provide a "Key" of expected measurements for self-checking.
A "Measurement Accuracy Log" where students' recorded data is checked against the teacher’s "Master measurements."
Dial or Digital Calipers, assorted mechanical parts.