PRECISION INSTRUMENTS EXPLAINED

• MICROMETERS

• CALIPERS

• GAGE BLOCKS

HOW PRECISE DO I NEED TO BE ?

WE NEED TO BE ABLE TO ACCURATELY MEASURE PARTS TO 1/1000 OF AN INCH OR AS A

DECIMAL - .001

.001 TENTHS THOUSANDS

HUNDREDS

Decimal to FractionDecimal to FractionConversionsConversions

.125 = 1/8”.125 = 1/8”

.250 = 1/4”.250 = 1/4”

.375 = 3/8”.375 = 3/8”

.500 = 1/2”.500 = 1/2”

.625 = 5/8”.625 = 5/8”

.750 = 3/4”.750 = 3/4”

.875 = 7/8”.875 = 7/8”

1. = 1”1. = 1”

.0625 = 1/16”.0625 = 1/16”

.1875 = 3/16”.1875 = 3/16”

.3125 = 5/16”.3125 = 5/16”

.4375 = 7/16”.4375 = 7/16”

.5625 = 9/16”.5625 = 9/16”

.6875 = 11/16”.6875 = 11/16”

.8125 = 13/16”.8125 = 13/16”

.9375 = 15/16”.9375 = 15/16”

MICROMETER PARTS

• Ratchet Screw• Thimble• Thimble Scale• Barrel• Barrel Scale• Frame• Spindle• Anvil

Divisions

0.025” Division

0.100” Division

0 1 2 3

0

0.001” DivisionBarrel

ScaleThimbleScale

Reading a Micrometer

• Observe the greatest 0.100-inch division on the barrel scale.

• Observe the number of 0.025-inch divisions on the barrel scale.

• Add the thimble scale reading (0.001-inch division) that coincides with the horizontal line on the barrel scale.

• Observe the greatest 0.100-inch division on the barrel scale. (three 0.100” = 0.300”)

0 1 2 3 10

5

• Observe the number of 0.025-inch divisions between the 0.300-inch mark and the thimble. (two x 0.025” = 0.050”)

0 1 2 3 10

5

• Add the thimble scale reading that coincides with the horizontal line on the barrel scale. (eight 0.001” = 0.008”)

0 1 2 3 10

5

Micrometer reading0.300”

0.050”

0.008”0.358”

+

TYPES OF CALIPERS

VENIER

DIAL

DIGITAL

OUTSIDE MEASURING JAWS BAR SCALE

• PARTS OF A CALIPER

• INSIDE MEASUREING JAWS • DIAL .001 DEPTH GAGE

0 1

10

2030

4050

60

70

80

90 0

0.100”1.000” 0.010” 0.001”

Divisions

Reading Calipers

• Observe the greatest 1.000” division

0 1

10

20

30

405

0

60

70

8 0

90

0

1.000”

0 1

10

2030

4050

60

70

80

90 0

•Observe the greatest 0.100” (0.100” = 0.600”)

0.600”1.000”0.600”

•Observe the greatest 0.010” (0.010” = 0.000”)

0.000”

0 1

10

2030

4050

60

70

80

90 0

1.000”0.600”0.000”

•Observe the greatest 0.001” (0.001” = 0.005”)

0 1

10

2030

4050

60

70

80

90 0

0.005” 1.000”0.600”0.000”0.005”+1.605”

GAGE BLOCKS AREVERY ACCURATE MEASURING STANDARDS TO 1\1,000,000 IN.

Project Lead The Way, Inc.®

Principles of EngineeringResource Guide

FIVE INDIVUAL GAGE BLOCKS FROM SET

RINGING TWO BLOCKS TOGETHER SO THEY ATTACH

GAGE BLOCKS RUNG TOGETHER TO GIVE AN ACCURATE SIZE