1. The English System of Measurement
Principles of EngineeringTM
Lesson 6.4 – Quality Assurance
Forging new generations of engineers
Project Lead The Way, Inc.
Copyright 2007

2. The English System of Measurement

3. How precise do I need to be?
We need to be able to accurately measure to the .001th
.125

4. Decimal to Fraction Conversions
.125 = 1/8”
.250 = 1/4”
.375 = 3/8”
.500 = 1/2”
.625 = 5/8”
.750 = 3/4”
.875 = 7/8”
= 1”
.0625 = 1/16”
.1875 = 3/16”
.3125 = 5/16”
.4375 = 7/16”
.5625 = 9/16”
.6875 = 11/16”
.8125 = 13/16”
.9375 = 15/16”

5. Tools used in Precision Measurement
Gage Blocks: These are used throughout industry as primary standards and have accuracy to a few millionths of an inch.

6. Gage Blocks

7. Micrometers
Sleeve
Ratchet Stop
Thimble

8. Dial Caliper

9. Dial Indicators