1. Precision Measuring Precision Measuring PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Precision Measuring
Design and Modeling
© 2011 Project Lead The Way, Inc.

2. Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Precision Measuring
Precision – How close together or repeatable the results are
A precise measuring instrument will give nearly the same result each time that it is used.
Accuracy – How close a measurement is to the accepted value
For example, a balance loaded with a standard 100 g weight should read 100 g. If it doesn’t, then the balance is inaccurate.
Precision measuring tools are used to improve precision and accuracy of measurement

3. Tools for Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Steel Rule
Micrometer

4. Tools for Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Digital Caliper
One of the most common tools for reverse engineering is the dial caliper because of its versatility.
Dial Caliper

5. Dial Caliper Parts Inside Measuring Faces Dial Clamp Screw Blade
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Dial Caliper Parts
Inside Measuring Faces
Dial
Clamp Screw
Blade
Fine Adjustment Screw
Dial Adjustment Screw
Outside Measuring Faces

6. { Reading a Dial Caliper The dial caliper is a precision measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
The dial caliper is
a precision measuring
instrument.
The caliper’s blade graduations are
in inches and tenths (.1) of an inch.
inch {
Each inch is broken into ten, for .1 of an inch.

7. Reading a Dial Caliper The caliper’s dial graduations are
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
The caliper’s dial graduations are
in thousandths (.001) of an inch.
The reference edge keeps track of larger increments; the dial is for smaller increments.

8. One full revolution of the pointer on the dial equals
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
One full revolution of the pointer
on the dial equals
one hundred thousandths (.100).

9. 2 Reading a Dial Caliper Step 1 Read inches from the blade
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Step 1
Read inches from the blade 2
1 in. – 6 in.

10. 2 3 Reading a Dial Caliper Step 2 Read tenths of an inch from
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Step 2
Read tenths of an inch from
the blade 2 3
1 in. – 6 in.
.0 in. -.9 in.

11. 2 3 2 8 Reading a Dial Caliper Step 3
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Step 3
Read thousandths of an inch from the dial 2 3
2 8
1 in. – 6 in.
.0 in.- .9 in.
.001 in in.

12. Dial Calipers Measure Thickness or Outside Diameter
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Dial Calipers Measure
Thickness or Outside Diameter

13. Dial Calipers Measure Thickness or Outside Diameter
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Dial Calipers Measure
Thickness or Outside Diameter
Inside Diameter or Space Width

14. Dial Calipers Measure Thickness or Outside Diameter
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Dial Calipers Measure
Thickness or Outside Diameter
Inside Diameter or Space Width
Depth

15. Dial Calipers Measure Thickness or Outside Diameter
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Dial Calipers Measure
Thickness or Outside Diameter
Inside Diameter or Space Width
Depth
Step Distance

16. Discussion Questions List measurement tools…
Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Discussion Questions
List measurement tools…
Steel Rule Tape Measure
Dial Caliper Meter Stick
Which of the tools listed would be best to use, and why, when measuring:
The hallway
Engineering Notebook
Pencil diameter
Height of your desk

17. Precision Measuring
PLTW Gateway®
Unit 1 – Lesson 1.3 – Measuring
Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved October 10, 2008, from
Wikimedia commons (2008). Retrieved October 15, 2008, from