Precision Measuring Tools
Participant Self-Paced
Workbook
Copyright © 2012 Boeing. All rights reserved.
Introduction
Course
Purpose
The purpose of this course is to introduce you to precision
measuring tools. In this course you will learn about
decimals and tolerances as well as how to use the following
tools:
•
•
•
•
Twelve-Inch Scale
Six-Inch Dial Caliper
Outside Micrometer (0-1) inch
Ball Gauges
Once you complete a topic, a skill check is available for
you to demonstrate what you have read and practiced.
Check your answers with those that are provided to see how
well you understood the material.
Topics
Covered
•
•
•
•
•
Course
Objectives
At the end of this course, you will be able to:
Determining Decimals and Tolerances
Using a Twelve-Inch Scale
Using a Six-Inch Dial Caliper
Measuring with an Outside Micrometer (0-1) inch
Using Ball Gauges with a Micrometer
Add and subtract decimals and determine the tolerance
range of given dimensions.
Use the following pieces of equipment to measure objects:
•
•
•
•
Copyright © 2012 Boeing. All rights reserved.
Twelve-Inch Scale
Six-Inch Dial Caliper
Outside Micrometer (0-1) inch
Ball Gauges
Objectives
Measurement
Your understanding of the section objectives will be
measured by your participation in the following activities:
•
•
•
•
•
•
Demonstrating how to add decimals and determine the
tolerance of a given number.
Converting fractions to decimal equivalents by using a
Decimal Equivalents Card
Using a scale to determine the correct length of several
items.
Using a Six-Inch dial caliper to determine the inside,
outside, and depth measurements of various items.
Using an outside micrometer to measure various items.
Using ball gauges and a micrometer to measure hole
sizes and check for hole size consistency.
Each section contains Skill Checks to assess your progress.
A comprehensive Final Test is administered at the
completion of the sections. You will be required to achieve
a grade of 80% or better in order to pass the Final Test.
Class Length
The time you need to complete the course depends on your
schedule and level of effort If you were to complete the
entire course in one session, you would need about 8 hours.
Copyright © 2012 Boeing. All rights reserved.
Materials
To complete this course you will be given the following:
•
•
•
•
•
•
•
•
•
•
•
New
Terminology
A Student Guide
A calculator
Pencils
Magnifying glass
Decimal Equivalents Card
Twelve inch Scale
0-1 inch outside Micrometer
Six-Inch Dial Caliper
Ball Gauges
Test kits containing items to measure
Final Test.
Tolerance – The degree of accuracy required for a
dimension, expressed as ‘plus or minus’ (+/-) a specific
amount.
Graduation – Marks on an instrument or tool that measure
degree or quantity.
Nominal – The dimension or quantity called out on an
Engineering drawing
Copyright © 2012 Boeing. All rights reserved.
I
C O N
D
E F I N I T I O N S
This icon is used to introduce a new section or topic.
This icon indicates that you will need to read the
materials.
This icon represents a handout or piece of equipment
that you should get from your class Facilitator. This
includes instruments as well as Skill Checks.
This icon indicates that there is some Skill Check that
you can do to reinforce what you just read. It also
represents the final Skill Check.
Copyright © 2012 Boeing. All rights reserved.
SECTION 1: U
TOLERANCES
S I N G
D
E C I M A L S
A N D
Introduction
To perform fabrication work, you must understand
decimal notation and tolerances. In this section, you will
learn about the decimal system and practice performing
math operations with decimals.
Objectives
At the end of this section, you will be able to:
• Convert fractions to decimal equivalents
• Add and subtract decimals.
• Determine the tolerance range (upper and lower
boundaries) of given dimensions.
• Calculator
• Decimal Equivalents Card
Resources
Decimal Values Linear dimensions on all FRPSDQ\ drawings are expressed
in decimal notation. This system allows engineers to
clearly specify the degree of accuracy, or tolerance, that is
required for any dimension. All linear measuring tools
used at PRVWFRPSDQLHV read in decimals. It is therefore important
that you be able to read and calculate decimals.
In decimal notation, inches are written to the left of a
decimal point, while fractions of an inch are written to the
right of a decimal point and are expressed in units of 10.
For example:
100.
Copyright © 2012 Boeing. All rights reserved.
=
One hundred inches
10.
1.
.1
.01
.001
.0001
Decimal Values
=
=
=
=
=
=
Ten inches
One inch
One-tenth of an inch
One-hundredth of an inch
One-thousandth of an inch
One-ten thousandths of an inch
Figure 2-1 shows the value of different positions on either
side of the decimal point for the number 1.1111.
Whole
Numbers
1
•
1
1
1
1
Whole Numbers
Decimal Point
Tenths
Hundredths
Thousandths
Ten Thousandths
Decimals
Figure 2-1: Value of positions on either side of the decimal
point.
Copyright © 2012 Boeing. All rights reserved.
The first number to the right of the decimal point is in
tenths of an inch. There are 10 tenths in one inch.
(.1000 x 10 = 1 inch). On the shop floor it is pronounced
as one tenth of an inch.
The second number to the right of the decimal is in
hundredths of an inch. There are 100 hundredths in one
inch (.0100 x 100 = 1). The number .010 is pronounced
one hundredth of an inch.
The third number after the decimal is in thousandths of an
inch and there are 1000 of them in one inch (.0010 x 1000
= 1 inch). The number .001 is pronounced one
thousandth of an inch.
When dimensions are carried out to four decimal places, it
is called ten thousandths of an inch. There are 10,000 of
these in each inch. (.0001 x 10,000 = 1 inch).
Copyright © 2012 Boeing. All rights reserved.
Review
The common shop way to read numbers is shown for each
of the numbers below.
•
2.8576
Two and Eight Hundred Fifty-Seven Thousandths and
Six-Tenths inches
•
4.050 inch
Four and Fifty-Thousandths inches
•
.0687 inch
Sixty-Eight Thousandths and Seven-Tenths inch
•
.500 inch
Five-Hundred Thousandths inch
•
.0067 inch
Six-Thousandths and Seven-Tenths inch
Pronunciation questions will NOT be included on the
Final Test.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
Write out how you would say each number in shop
language on the line provided. When you are done, check
your answers against the answers on the following page.
1. .451
______________________________________________
______________________________________________
2. .897
______________________________________________
______________________________________________
3. 5.155
______________________________________________
______________________________________________
4. 7.1544
______________________________________________
______________________________________________
5. 3.2563
______________________________________________
______________________________________________
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
Answers
Check your answers from the previous page.
1. Four hundred fifty-one thousandths
2. Eight hundred ninety-seven thousandths
3. Five and one hundred fifty-five thousandths
4. Seven and one-hundred fifty-four thousandths and
four-tenths
5. Three and two-hundred fifty-six thousandths and
three-tenths
Copyright © 2012 Boeing. All rights reserved.
In most cases, a measurement requirement will be given to
you in a decimal format. By using the Decimal Equivalents
Card you can easily convert a fraction to a decimal.
Converting
Fractions to
Decimal
Equivalents
Converting
Fractions to
Decimals
Simply find the fraction on the left side of the card and read
its decimal equivalent on the right side of the card. For
example, ¼” is the same as .250”.
Exercise #1
You are asked to get a 5/16 drill bit. Because drill bits are
usually measured in decimal sizes, you look at your drill
card and notice that 5/16” corresponds with .3125 inches.
When you go to the tool issue area, you ask for a .3125 drill
bit rather than a 5/16.
Using your Decimal Equivalents Card, practice doing a few
conversions in the exercise below. The answers are
provided to assist you in making these conversions and
understanding how to use the card.
Fraction
Decimal Equivalent
3/8
__.3750______________
13/16
__.8125______________
1/8
__.1250______________
If you need help to complete this exercise, ask your
facilitator for assistance. Continue practicing until you are
comfortable with the conversion process.
Copyright © 2012 Boeing. All rights reserved.
Skill Check
1
Convert the fractions listed below to decimal equivalents.
Check your answers on the next page.
1. 7/16
2. 9/32
3. 3/8
4.
25
5.
15
/64
is equivalent to ______________
is equivalent to ______________
is equivalent to ______________
/16 is equivalent to ______________
6. 1/2
7. 3/32
Copyright © 2012 Boeing. All rights reserved.
is equivalent to ______________
is equivalent to ______________
is equivalent to ______________
Skill Check
1
Answers
Listed below are the answers to the Decimal Conversion
Skill Check from the previous page.
1. .4375
2. .2812
3. .3750
4. .3906
5. .2344
6. .5000
7. .0938
If you are comfortable with converting fractions to
decimals with the Decimal Equivalent Card, move on to the
next subject. If you are unsure of the conversion process,
have your facilitator assist you.
Copyright © 2012 Boeing. All rights reserved.
To add or subtract decimals, place the numbers in a column,
aligning the decimal points. Add or subtract the numbers in the
column, keeping the decimal point in the solution.
Adding and
Subtracting
Decimals
Example 1
Find the sum of 2.43, 1.485, 0.3, 12.02, and 0.074
Solution:
2.43
1.485
0.3
12.02
0.074
16.309
Adding
Decimals
or
2.430
1.485
0.300
12.020
0.074
16.309
1.485 and 0.074 have three decimal places, while 2.43, 0.3,
and 12.02 only have one or two decimal places.
Adding zeroes after 2.43, 0.3, and 12.02 so that they each have
three decimal places makes it easier to keep the column
straight:
2.430
0.300
12.020
Now all of the numbers have three decimal places and the
column of numbers is easier to read. Adding zeroes to the end
of these numbers does not change the value of the numbers.
________________________________________________
Example 2
Find the difference between 17.29 and 6.147
Solution:
17.29
-6.147
11.143
Copyright © 2012 Boeing. All rights reserved.
or
17.290
-6.147
11.143
Skill Check 2
Add or subtract the following numbers and write your
answers in the space provided. When you are finished,
check your answers with the answer key on the next
page.
Do NOT use a calculator for this part of the Skill Check.
Be sure that the decimal point is correctly placed in each
of your answers.
a) .2 + .07 + .5
=
b) 2.6 + 22.4 + .03
=
c) 22.8 + 5.009 + 613.2
=
d) .005 + 5 + 16.2 + .96
=
e) 28.74 – 16.32
=
f) 15.4 + 22 + .01 + 1.48
=
g) .005 – .0005
=
h) 1.431 – .562
=
i) 1.0020 – .2
=
j) 8.04 – 7.96
=
Copyright © 2012 Boeing. All rights reserved.
______________
______________
______________
______________
______________
______________
______________
______________
______________
______________
You may use a calculator for the following problems.
k) 72.306 + 18.45 – 27.202
=
__________
l) 14 – 6.3 + 2.739
=
__________
m) 27.65 + 18.402 – 2.39 + 7.63
=
__________
n) 18.0006 + 14.005 + 12.34
=
__________
o) 93.8 – 16.4327 – 20.009
=
__________
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2
Answers
If you answered at least 12 of the 15 problems correctly,
go onto the next section of this section. If you answered
fewer than 12 problems correctly, review Adding And
Subtracting Decimals (page 19), then do Skill Check 2
again. You may also ask the facilitator for assistance.
a) .2 + .07 + .5
=
.77
b) 2.6 + 22.4 + .03
=
25.03
c) 22.8 + 5.009 +613.2
=
641.009
d) .005 + 5 + 16.2 + .96
=
22.165
e) 28.74 – 16.32
=
12.42
f) 15.4 + 22 + .01 +1.48
=
38.89
g) .005 - .0005
=
.0045
h) 1.431 - .562
=
.869
i) 1.0020 - .2
=
.802
j) 8.04 - 7.96
=
.08
k) 72.306 + 18.45 – 27.202
=
63.554
l) 14 – 6.3 + 2.739
=
10.439
m) 27.65 + 18.402 – 2.39 + 7.63
=
51.292
n) 18.0006 + 14.005 + 12.34
=
44.3456
o) 93.8 – 16.4327 – 20.009
=
57.3583
Copyright © 2012 Boeing. All rights reserved.
Dimensions &
Tolerances
Now that you have learned how to add and subtract
decimals, it’s time to apply your knowledge to
Dimension Tolerances.
A dimension listed on a drawing is called a nominal
dimension. Tolerances tell us how much discrepancy is
allowed from the nominal dimension.
How much tolerance is allowed for a dimension is
indicated by a plus (+) or minus (-) sign. The following
are examples of tolerances, starting with ‘plus or minus
four ten thousandths’.
•
•
•
•
Copyright © 2012 Boeing. All rights reserved.
+/- .0004
+/- .008
+/- .01
+/- .3
Drawing
Tolerances
To determine the biggest dimension allowable, add the
tolerance to the nominal dimension. To determine the
smallest dimension allowable, subtract the tolerance
from the nominal dimension.
Example:
A drawing requires a hole to be .39” from the edge. The
tolerance is +/- .03”.
To find the biggest dimension allowable, add .03 to .39.
.39
+ .03
.42
To find the smallest dimension allowable, subtract .03
from .39
.39
- .03
.36
For the nominal dimension of .39” in this drawing, the
largest allowable dimension is .42”. The smallest
allowable dimension is .36”.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 3
Determine the largest and smallest acceptable
dimensions for the numbers below and write your
answers in the space provided. When you are finished,
check your answers against the Skill Check answer key
on the next page.
If you would like more decimal practice, review this
section and then complete the Optional Skill Check that
follows the Skill Check 3 answer key.
Largest
Smallest
a. 6.305 +/- .010
_____________ _____________
b. 12.430 +/- .03
_____________ _____________
c. .097 +/- .005
_____________ _____________
d. 5.0 +/- .1
_____________ _____________
e. 28.78 +/- .03
_____________ _____________
f. 72.229 +/- .010
_____________ _____________
g. 16.432 +/- .002
_____________ _____________
h. .250 + 001/ -.000 _____________ _____________
Copyright © 2012 Boeing. All rights reserved.
i. 5.97 +.00/-.03
_____________ _____________
j. 1.402 +.10/-.00
_____________ _____________
k. 1.562 +/- .000
_____________
_____________
Skill Check 3
Answers
Check your numbers with the answers below.
Largest
Smallest
a. 6.305 +/- .010
6.315
6.295
b. 12.430 +/- .03
12.460
12.400
.102
.092
5.100
4.900
e. 28.780 +/- .03
28.810
28.750
f. 72.229 +/- .010
72.239
72.219
g. 16.432 +/- .002
16.434
16.430
.251
.250
i. 5.970 +.00/-.03
5.970
5.940
j. 1.402 +.10/-.00
1.512
1.402
k. 1.562 +/- .000
1.562
1.562
c. .097 +/- .005
d. 5.0 +/- .1
h. .250 + 001/ -.000
Copyright © 2012 Boeing. All rights reserved.
Optional Skill Check: Adding and Substracting Decimals
Add and subtract the following decimals. Record your
answers in the space provided. When you are finished,
compare your answers with the Skill Check 4 answer key
on the next page.
Skill Check 4
1.
14.29 – 6.305 – 3.47265
=
_______________
2.
34.229 – 5.0043 + 4.762
=
_______________
3.
6.0001 - .0002 + 4.0001
=
_______________
4.
887.993 - .093 + 45.004
=
_______________
5.
3.229 +6.921 – 9.333
=
_______________
6.
7.89+45 – 50.856
=
_______________
7.
6.52 + .526 – 2.58
=
_______________
8.
3.33 +.333 + .033
=
_______________
9.
43.043 – 23.43 – 10.4
=
_______________
6.063 - .063 + 4.062
10.
Write how you would say the following:
=
_______________
11. 9.4289
______________________________________________
______________________________________________
12.
2.5192
______________________________________________
______________________________________________
Copyright © 2012 Boeing. All rights reserved.
Optional Skill Check Answers: Adding and Substracting Decimals
Skill Check 4
Answers
1. 14.29 – 6.305 – 3.47265
=
4.51235
2. 34.229 – 5.0043 + 4.762
=
33.9867
3. 6.0001 - .0002 + 4.0001
=
10.
4. 887.993 - .093 + 45.004
=
932.904
5. 3.229 +6.921 – 9.333
=
.817
6. 7.89 +45 – 50.856
=
2.034
7. 6.52 + .526 – 2.58
=
4.466
8. 3.33 +.333 + .033
=
3.696
9. 43.043 – 23.43 – 10.4
=
9.213
=
10.062
10. 6.063 - .063 + 4.062
Write how you would say the following:
11. 9.4289
Nine inches, four-hundred twenty-eight thousandths
and nine-tenths
12. 2.5192
Two inches, five-hundred nineteen-thousandths and
two-tenths.
Copyright © 2012 Boeing. All rights reserved.
Summary
During this section you were introduced to Decimals and
Tolerances. You learned that whole numbers are placed
to the left of the decimal. Fractions (tenths, hundredths,
and thousandths are placed to the right of the decimal.
You practiced using a Decimal Equivalents Card for
converting fractions to decimals.
You also practiced adding and subtracting decimals.
You were introduced to the concept of tolerances and
methods to determine tolerance ranges.
If you are comfortable with this section, proceed to the
next. Otherwise, review this section and ask your
facilitator for further assistance, if necessary.
Copyright © 2012 Boeing. All rights reserved.
S
E C T I O N
2: U
S I N G
A
S
C A L E
Introduction
Many manufacturing jobs require you to perform
measurements using a scale. In this section you will:
• Learn how to read a scale
• Measure several manufacturing parts
• Perform five Skill Checks
Objectives
At the end of this section, you will be able to:
• Use a Scale to measure specific manufacturing parts
in inches.
Resources
Copyright © 2012 Boeing. All rights reserved.
• Twelve-Inch Scale
• Sharpened pencil
• Various manufacturing parts
Introduction
In this section you will be using a Twelve-Inch Scale.
Most scales have fractions marked on one face (halves,
quarters, sixteenths of an inch) and decimals marked on
the other face (tenths and hundredths of an inch). Since
Engineering drawings use decimals, we will be using the
face that is marked with decimal measurements.
Decimal
Fractional
Figure 3-1: Scale dimensions on each side of the scale
Copyright © 2012 Boeing. All rights reserved.
Reading the
Scale
Study the figure below to become familiar with the
graduations on a scale.
Tenth
(.2)
(.2)
Tenth
Inch
(1)
(.64)
Hundredth
Figure 3-2: Decimal Graduation on a Scale.
Copyright © 2012 Boeing. All rights reserved.
(2)
Inch
Reading the
Decimal Scale
The upper half of the scale is marked with inches and
tenths of an inch. The lower half of the scale is marked
with inches, tenths of an inch, and hundredths of an inch.
To read a scale, place the scale against the item to be
measured, and follow these four steps:
1.) Read and record the closest value to the left in inches
(1,2,3, etc.)
2.) Read and record the closest value to the left in tenths
of an inch (.1, .2, .3, etc.)
3.) Read and record the closest value to the left in
hundredths of an inch (.01, .02, .03, etc.)
4.) Add these numbers to determine the complete
measurement.
If the reading line falls exactly on an inch mark or tenth of
an inch mark, record that number. Don’t record the
number to the left.
Example: If the reading line fell between 2 and 3 inches at
exactly three tenths, the measurement would be 2.30”.
Also note that you would not record hundredths of an inch
because the reading was exactly on the three tenths line.
Figure 3-3: Reading the Scale
Copyright © 2012 Boeing. All rights reserved.
Practice
Reading the
Decimal Scale
Refer to Figure 3-3. Looking at the upper half of the
scale, notice that the reading is between 2 and 3 inches.
Record the number to the left, which is 2.0. The reading
so far is 2.0 inches.
Looking closer, you can also see that the reading is
between the 3 tenths and 4 tenths marks (between .3 and
.4). Record the number to the left of the reading, which is
.3. You now know that the reading is a little more than 2.3
inches.
Now look at the bottom edge of the scale for a more
precise measurement. The smallest graduation marks are
hundredths of an inch. The reading aligns with the fourth
mark after 2.3, which is four one hundredths of an inch, or
.04”. That means that the reading is 2.34”.
2.0
.3
.04
2.34
If a dimension requires a measurement in thousandths of
an inch, you will need to use a more precise measuring
tool than a scale.
Copyright © 2012 Boeing. All rights reserved.
Steps to follow
when reading a
scale
To read a scale, follow these steps:
1. Read and record the next lower inch value (1.0)
2. Read and record the next lower tenths value (.1)
3. Read and record the next lower hundredth value (.01)
Remember, if the reading line is exactly on an inch, tenth
or hundred, that is the number you record, not the next
lower one.
Skill Check 1
Calculate the reading on the scale below and record your
answer on the line below.
Answer: _________________
Compare your answer with the answer key on the next
page.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
Answer
The correct reading is 4.78.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2
Below is a scale with arrows pointing to several locations
on the scale. Read the scale and record your answer on the
corresponding line. When you have finished, check your
answers on the following page.
Record your measurements
here:
A. ____________
B. ____________
C. ____________
D. ____________
E. ____________
F. ____________
G. ____________
H. ____________
I. ____________
J. ____________
K. ____________
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2
Answers
Check your answers. If you missed more than 3, review
the previous section before proceeding. It will help you to
understand the rest of this section.
A. .90
E.
.81
I. 2.55
B. 2.80
F. 1.37
J. 2.73
C. .26
G. 1.59
K. 2.96
D. .57
H. 2.12
Notice that zeroes have been added to the end of some of
the answers. Remember that this does not change the
value of the numbers.
Copyright © 2012 Boeing. All rights reserved.
Taking Readings
with a Scale
Once you know how to read the scale, you can use it to
measure between lines:
1. Set the scale so that the zero end of the scale is even
with the first line, as in figure 3- 4.
2. Read the scale values that line up with the reading
line, which is behind the scale.
3. Record your reading.
Reading line = 1.16
Figure 3-4: Scale with Reading Line.
Many people prefer to start a measurement at the one-inch
mark, as shown in Figure 3-5. This practice is called
‘burning an inch’ and provides a more accurate
measurement if the end of your scale is in poor condition.
When burning an inch, be sure to subtract an inch from
your reading.
Burning an
Inch
Point being
measured from
Figure 3-5 : Burning an inch (This reads 1.16.)
Copyright © 2012 Boeing. All rights reserved.
Keep the scale perpendicular to the marks or edges you
are measuring. If the scale is at an angle, the accuracy of
your measurement will be decreased, as shown on the
right side of Figure 3-6.
Ensuring
Accuracy
Figure 3-6: Correct and incorrect placement of the scale
Measuring
Between the
Lines
When measuring between hand-drawn lines, place the
edge of the scale in the middle of the first line, as shown
on Fig. 3-7. Take your reading from the middle of the
second line (the reading line). This will ensure that your
measurements are accurate, no matter how thick the lines
are. For example, the lines on a typical layout are usually
about .03” thick.
Figure 3-7: Measuring on a layout
Copyright © 2012 Boeing. All rights reserved.
Hole Locations
When measuring between marks representing hole
locations, as shown in Figure 3-8, measure where the
lines intersect. This measures the center of the hole
accurately, even if the lines have not been drawn
perpendicularly.
Figure 3-8. Measuring from hole to hole
Measuring from Measure from center point to center point of each hole
with your scale (Figure 3-9). The accuracy of this method
Hole to Hole
depends on your ability to visualize the hole centers. With
small holes this can be easy, but if you are measuring
large diameter holes, you may have to use a different
precision measuring tool to find the center of the hole.
Figure 3-9: Measuring from center point to center point.
Copyright © 2012 Boeing. All rights reserved.
If you have holes of the same diameter, you can measure
from the leading edge of the first hole to the leading edge
of the second hole in order to get the centerline separation
dimension (Figure 3-10).
Figure 3-10: Measuring between holes of the same diameter.
Another method that can be used is to measure from the
inside edge of the first hole to the inside edge of the
second hole. Then add ½ the diameter of hole 1 plus ½
the diameter of hole 2 to get the centerline separation
dimension (Figure 3-11).
Figure 3-11: Measuring between holes of different diameters.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 3
Measure the ten lines on this page and record your
answers in the spaces below. When you are done, check
your answers with the answer key on the following page.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
1. ________________
6. _________________
2. ________________
7. _________________
3. ________________
8. _________________
4. ________________
9. _________________
5. ________________
10._________________
Copyright © 2012 Boeing. All rights reserved.
Skill Check 3
Answers
Check your answers from the previous page. Did you get
them all right? If you did, great! If not, you might want
to go back and check your answers before moving on to
the next section.
1.
.620
6. 1.990
2.
.770
7. 2.360
3.
.930
8. 2.830
4. 1.270
9. 3.470
5. 1.760
10.4.180
Copyright © 2012 Boeing. All rights reserved.
Skill Check 4
Now that you have practiced using a scale on paper, it is
time to use it on several of the items you may be required
to measure in the shop.
In this Skill Check you will measure five dimensions on a
step block. Record your measurements on the lines below,
then check the answer key on the next page.
a.
a
b.
b
c.
d
c
d.
e.
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e
Skill Check 4
Answers
Check your answers from the previous page. If any of
your answers are significantly different from the ones
below, recheck your measurements before moving on to
the next section. Ask your facilitator for assistance, if
needed.
a. 2.000
b. 5.000
c. 6.100
d. .389
e. 2.000
Copyright © 2012 Boeing. All rights reserved.
Making
Layouts with
the Scale
A scale is useful for performing layouts that need only to
be accurate to +/- .020. For example, a scale can be used
to mark a hole pattern on a block in preparation for
drilling.
Using Sketch 1 as a model, use the box in Sketch 2 to lay
out a line, following the directions below.
.60 inch
Sketch 1
1. On the left side of the box below, measure .60 inches
from the top of the box. Make a small mark at the .60
location.
2. Then, measure .60 inch from the top of the right side
of the box and mark it as you did in step one.
3. Now align the edge of the scale with the two marks
you just made. Use the edge of the scale to draw a line
between the two marks.
Sketch 2
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4. Have the facilitator check your work for accuracy.
5. Next you will draw vertical lines. First, lay out another
horizontal line at .60 inches, using the box in Sketch 4.
6. Now you will lay out 3 vertical lines in the Sketch 4
box that are 1.00”, 1.40”, and 2.40” long. To lay out
vertical lines, start your measurement from the left
side of the box. Use Sketch 3 as a model. Place the end
of your scale on the left side of the box. Mark off
1.00” at the top and at the bottom of the box.
7. Now connect the marks by drawing a vertical line.
Repeat the process to draw the 1.40” and 2.40” lines.
Have the facilitator check your work for accuracy.
.60”
2.40”
1.40”
1.00”
Sketch 3: Laying out vertical lines
Sketch4
Copyright © 2012 Boeing. All rights reserved.
Skill Check 5
Using your scale and the boxes below, lay out lines
according to the measurements given. When you are
done, have the facilitator check your work.
Exercise 1:
Horizontal:
.55 from top
Vertical:
.79, 1.35, and 2.05 from left
Exercise 2:
Horizontal:
.40 from top
Vertical:
.65, 1.05, and 1.79 from left
Exercise 3:
Horizontal:
.48 from top
Vertical:
1.18, 1.50, and 2.12 from left
Copyright © 2012 Boeing. All rights reserved.
In this section you were introduced to the scale as a
tool used to perform measurements. You learned that
the scale has two faces that are marked with decimals
and fractions. You measured various objects and
learned several techniques for measuring, including:
Summary
•
•
•
•
Burning an inch
Measuring between lines
Measuring hole locations
Measuring from hole to hole
In this section you also learned how to make layouts with
a scale.
If you are comfortable with using the scale, proceed to the
next section. Otherwise, review any area that you had
difficulty with or ask your facilitator for assistance.
Copyright © 2012 Boeing. All rights reserved.
SECT
CALI
I O N 3
P E R S
Introduction
Objectives
: U
S I N G
S
I X
-I
N C H
D
I A L
In this section you will learn how to read and use a Six-Inch
Dial Caliper. The Dial Caliper is used to measure inside
measurements, outside measurements, round stock, square
stock, plates, counter bores, bushings and depths.
Each participant will be able to:
• Use a Six-Inch Dial Caliper to take inside and
outside measurements that are accurate to within
+/- .005.
• Demonstrate how to determine the accuracy of a
Six-Inch Dial Caliper.
Skill Check
At the end of this section, you will be expected to use a
Six-Inch Dial Caliper to accurately measure objects to 3
decimal places.
Resources
Copyright © 2012 Boeing. All rights reserved.
•
•
Six-Inch Dial Caliper
Manufacturing parts to measure
Dial Caliper
Introduction
A Six-Inch Dial Caliper is a precision-measuring tool that
measures accurately to within .001 of an inch. Although it
is not as accurate as a Vernier Scale Micrometer (which can
read to within .0001 of an inch), the Six-Inch Dial Caliper is
more versatile.
You can use the Six-Inch Dial Caliper to measure distance
from 0 to 6 inches for inside, outside, and depth
measurements. Because of its versatility, you will use this
tool frequently.
A Dial Caliper has jaws that contact inside and outside
surfaces during measurements, and a rod connected to a
slide for obtaining depth dimensions. The end of the rod is
notched to provide a nib for measuring small grooves and
recesses.
All readings are taken directly from the bar and dialindicator. Knurled thumbscrews lock the movable jaw and
adjustable indicator dial.
With the addition of a depth attachment, the Dial Caliper
becomes as convenient and easy to use as a depth gauge.
Copyright © 2012 Boeing. All rights reserved.
Dial Caliper Parts
G
E
B
C
A
D
F
C
B
Figure 4-1: Parts of a Dial Caliper
Parts of the
Dial Caliper
The major parts of the Dial Caliper are labeled on the
diagram and described below:
A. Bar: A scale with graduations in inches and tenths of an
inch.
B. Fixed Jaws: Located at the zero end of the scale on the
bar, the fixed jaws function as the starting points for
inside and outside measurements.
C. Moveable Jaws: Can be slid along the bar in order to
take inside and outside readings.
D. Dial: The dial hand makes one complete revolution for
each .10 inch of movement. The face is divided into
increments of .001.
E. Moveable Jaw Clamp Screw: This locks the movable
jaws into place.
F. Adjusting Nut: This is used to adjust to the dial so that
it registers zero when the caliper jaws are closed.
G. Depth Bar: Used to take depth measurements of holes,
steps, and recesses.
Copyright © 2012 Boeing. All rights reserved.
Reading the
Dial and Bar
Once you have placed the jaws in the space or around the
part that you want to measure, you need to read both the bar
and the dial to get a reading.
The bar is in increments of inches and tenths. As you slide
the bar to the right, new increments appear from under the
dial. In Figure 4- 2, the reading is something over .700”.
Figure 4-2. Reading the bar and dial
One full rotation of the dial (zero to zero) represents a
movement of .100 inch. The dial reads in thousandths and
ten thousandths.
In Figure 4-2, the last line visible on the bar is .700 and the
dial reads .050, so the reading on this measurement is .750.
Copyright © 2012 Boeing. All rights reserved.
Figure 4-3. Reading the bar and dial
The bar reads 3 tenths and the dial reads 12 thousandths, so
the reading is:
.300 + .012 = .312”
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
Dial Caliper
Read the bar and dial in each photo below, then record
your reading in the space provided. When you are done,
check your answers with the answer key following this
Skill Check.
1.
_________
2.
__________
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3.
_______
4.
_______
5.
_______
Copyright © 2012 Boeing. All rights reserved.
6.
_______
7.
_______
8.
_______
Copyright © 2012 Boeing. All rights reserved.
9.
_______
10.
_______
11.
_______
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
Answers
Below are the answers to the previous exercise. How did
you do? If you missed more than 3 you may want to do a
little more practice reading the dial. If you got them all
right, congratulations!
1. .966
2. .357
3. .665
4. .485
5. 1.003
6. 1.321
Copyright © 2012 Boeing. All rights reserved.
7. 1.100
8. .927
9. 1.490
10. 1.173
11. 1.962
Dial calipers can perform three types of measurements:
Types of
Measurement
• Outside surfaces
Using a Dial
• Inside surfaces
Caliper
• Depth measurements
Each of these measurements is taken with the inside or
outside jaws or the depth bar.
Note: Always make sure that the object you want to
measure is clean and free of burrs, or your measurement will
not be accurate.
Perform the following steps to measure the outside diameter
Outside
of an item from your kit:
Measurement
1. Place your left hand on the fixed jaws. Place your right
hand around the bar with your thumb on the sliding bar.
2. With your right-hand thumb, slide the movable jaw away
from the fixed jaw.
3. Slide the movable jaw out until the opening between the
jaws is slightly larger than the width of the item you are
measuring.
4. Hold the item against the fixed jaw and slide the movable
jaw inward until the movable jaw is touching the item.
5. Rock the caliper slightly to make sure it is perfectly
square on the item, while adjusting for final feel and
setting.
6. The measuring surfaces of the caliper must be square on
the material in order to get an accurate measurement.
7. Read the measurements on the bar and the dial.
Copyright © 2012 Boeing. All rights reserved.
Figure 4-4: Incorrect and correct placement of calipers
Caring for
the Dial
Caliper
Dial Calipers must be handled with care to preserve their
accuracy. Some of the things you can do to increase the life
of your calipers include:
•
Keep your calipers and measuring surfaces clean.
•
Keep your calipers in a case, with the jaws slightly open.
If they are stored in the closed position, condensation
may form, causing the surface to corrode, and destroying
the caliper’s accuracy.
•
Regularly check to see that zero lines on the caliper
scales align when the jaws are closed.
•
Keep your tool certification up to date. All calipers used
in critical applications must be certified. Most tool room
personnel can address your certification requirements.
Copyright © 2012 Boeing. All rights reserved.
How to
Check the
Accuracy of
the Dial
Caliper
Checking the accuracy of the Dial Caliper requires a few
simple steps:
1. Ask your classroom facilitator for a gauge block with a
known thickness.
2. Place the gauge block in the jaws and measure the gauge
block.
3. If the reading doesn’t correspond with the gauge block
thickness, use the caliper adjustment knob to move the
dial until it corresponds with the thickness of the gauge
block. This will reset the Dial Caliper.
Ensuring
Accuracy
Perform the following steps before using your calipers:
• Check your gauge block reading. Have the facilitator
verify that you are making the correct reading.
• Ensure that the surfaces of the caliper are clean.
• Verify that the zero lines on the scale align when the
jaws are closed. If they do not, return the caliper to the
classroom facilitator and get another one.
• Check that the sides of the block are clean.
• Measure the block again by repeating the procedure.
When measuring round objects, you need to be especially
careful about holding the caliper jaws square to the surface
of the object. You are looking for the smallest reading you
can get without forcing the caliper jaws hard against the
object.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2
Large:
A. _________
Use the corresponding materials from your kit to perform
the measurements indicated. Record your dial caliper
measurements in the spaces provided. When you are done,
check your answers with your classroom facilitator.
Large & Small
Dowel Pins
B. _________
A
B
C
D
Small:
C. _________
D. _________
Large:
A. _________
Large & Small
Locating Pin
Liners
A
C
B. _________
Small:
C. _________
D. _________
Copyright © 2012 Boeing. All rights reserved.
B
D
A. _________
Plate
B. _________
A
C. _________
C
B
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2
Answers
Check your numbers with the answers below. If any of
your answers are significantly different, re-measure the
material and check your answer again. Ask the facilitator
for assistance, if needed.
Large:
A. _ .375___
Large & Small
Dowel Pins
B. _2.000 __
Small:
C. _ .187___
D. _2.000___
Large:
A. _.501__
Large & Small
Locating Pin
Liners
B. _.620 _
Small:
C. _.407__
D. _.560__
Plate
A. _ .125___
B. _1.700 to
2.000__
C. _1.700 to
2.000__
Copyright © 2012 Boeing. All rights reserved.
For Inside Measurements
Figure 4-5:Caliper jaws used for inside measurement.
To take an inside measurement, follow the same procedures
Inside
Measurement as the outside dimension method, but use the inside jaws of
the calipers (Figure 4-5).
To measure inside diameter:
1. Select one of the bushings from your materials kit.
Measure the hole in either end of the bushing:
2. Slide the movable jaw so that points of the inside jaws
are open a little less than the hole to be measured in the
bushing.
Copyright © 2012 Boeing. All rights reserved.
3. Use your thumb to pull the movable jaw out until it just
touches the side of the bushing.
4. Rock the caliper slightly, moving one end of the caliper
gently back and forth. You are looking for the largest
reading you can get without forcing the jaws against the
bushing. There should only be a very slight resistance
between the jaws and the surface of the bushing. (See
Figure 4-6.)
5. Once you have achieved the proper feel of the jaws in the
bushing, snug down the moveable jaw clamping screw.
6. Read the bar scale and the dial to determine the
measurement.
Figure 4-6: Incorrect and correct placement of caliper jaws
Copyright © 2012 Boeing. All rights reserved.
Skill Check 3
Record the dial caliper measurements for your bushing, as
indicated below. When you are done, check your
measurements with the answers on the following page.
1. ___________ Slot Side
2. ___________ Flat Side
3. ___________ Outside Slot
Copyright © 2012 Boeing. All rights reserved.
Skill Check 3
Answers
Check your numbers with the answers below. If any of
your answers are significantly different, re-measure the
material and check your answer again. Ask the facilitator
for assistance, if needed.
1. __.406_____
Slot Side
2. ___.250____
Flat Side
3. ___.063____
Outside Slot
Copyright © 2012 Boeing. All rights reserved.
The depth-measuring device on a Dial Caliper consists of an
Taking a
adjustable rod, called the depth bar. The depth bar extends
Depth
Measurement from the end of the caliper bar.
Figure 4-7: Taking a depth measurement
The body of the dial caliper rests on a precision surface that
functions as a fixed jaw for taking a depth measurement.
The depth bar functions as the movable jaw.
The depth bar can measure the depth of holes, the height of
steps, or the thickness of an object.
Copyright © 2012 Boeing. All rights reserved.
Using the
Depth Bar
Figure 4-8: Measuring depth with a depth bar.
To measure depth, perform the following steps:
1. Place the block from your materials kit on the table with
the step facing up, as in Figure 4-8.
2. Slide the movable jaw so that the depth bar is protruding
a shorter distance than the depth of the step in the block.
3. Place the end of the depth bar flush against the edge of
the step, with the bar on top of the step. Be sure you are
holding the caliper perpendicular to the surface in both
directions.
Copyright © 2012 Boeing. All rights reserved.
Figure 4-9: Correct placement of depth bar
4. Use your thumb to move the depth bar until it’s just
touching the vertical surface, and snug down the
movable jaw clamping screw.
5. Now read the dial and bar scale to determine the
correct measurement.
Copyright © 2012 Boeing. All rights reserved.
The correct reading for the depth of the step shown in
Figure 4-8 is .489”. Check with the facilitator if you did
not get the correct reading,
•
Check the caliper and the block for cleanliness.
•
Try again, paying particular attention to keeping the
caliper perpendicular to the work piece in all
directions.
Any deviation from perpendicular reduces your
accuracy. Because the end of the caliper is so small, it is
often difficult to get an extremely accurate depth
reading with it.
Copyright © 2012 Boeing. All rights reserved.
Measuring the
Depth of a Hole
Now let’s take a depth measurement of a hole.
Figure 4-10: Measuring a hole with the depth bar.
1. Place the block from your kit on the table.
2. Place the dial caliper so that the bottom edge is over
a hole, as in Figure 4-10.
3. Slide the movable jaw until the depth bar is
protruding into the hole, but not touching the bottom
of the hole. The end of the caliper bar should be
touching the surface of the block on either side of the
hole.
4. Holding the caliper so that the end is flat against the
surface of the block, gently slide the movable jaw
downward until you feel the end of the depth bar just
touch the surface of the table at the bottom of the
hole. Do not allow it to push the end of the caliper
bar away from the surface of the block.
5. Tighten the movable jaw clamping screw.
6. Read the bar scale and dial.
Copyright © 2012 Boeing. All rights reserved.
Figure 4-11 illustrates incorrect and correct positioning
of the dial caliper when taking depth measurements.
Figure 4-11: Incorrect and correct positioning of depth
bar.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 4
Record the dial caliper measurement you take for each
dimension indicated. When you are done, check your
measurements with your facilitator.
a. __________
Large
Drill
Bushing
b. __________
a
c. __________
b
c
a. __________
Step Block
b. __________
c. __________
d. __________
e. __________
Copyright © 2012 Boeing. All rights reserved.
c
a
e
b
d
Skill Check 4
Answers
Check your numbers with the answers below. If any of
your answers are significantly different, re-measure the
material and check your answer again. Ask the facilitator
for assistance, if needed.
a. __.125____
Large Drill
Bushing
b. _ .312____
c. _ .437____
a. __.980____
Step Block
b. __.485____
c. __.998____
d. __.481____
e. _1.113____
Copyright © 2012 Boeing. All rights reserved.
Summary
In this section, you learned that the dial caliper can measure
inside measurements, outside measurements, round stock,
square stock, counter bores and depths. You were given
several exercises, and then measured various items. You also
read about the importance of keeping your dial caliper clean
and in good working order.
Review any material that you found difficult. Ask your
facilitator for any needed assistance.
When you are comfortable with using a dial caliper, proceed to
the next section.
Copyright © 2012 Boeing. All rights reserved.
SECTION 4: M
MICROMETER
E A S U R I N G
W I T H
A N
O
U T S I D E
Introduction
In this section you will learn how to measure using an
outside micrometer. You will learn about the various
functions of a micrometer, its components, and how to read
the thimble and reading line.
Objectives
At the end of this section you will be able to:
• Accurately measure objects to 4 decimal places.
• Demonstrate how to determine the accuracy of a
micrometer.
Skill Check
At the end of this section, you will be expected to use an
outside micrometer to accurately measure objects to 4
decimal places.
Resources
Copyright © 2012 Boeing. All rights reserved.
• 0 – 1 inch outside micrometer
• Materials kit
Introduction to
the 0-1 inch
Outside
Micrometer
The micrometer is a measuring tool designed to provide
extremely accurate measurements (see Figure 5-1). Some
micrometers can measure objects as small as tenthousandths of an inch.
At the core of a micrometer is a large screw. Pitch is the
distance between the peak of one screw thread to the peak
of the next screw thread. The screw inside a 0-1inch
outside micrometer has a pitch of forty threads per inch.
One-fortieth of an inch is 0.025 (0.025” x 40 = 1.000”).
This means that every time the micrometer handle
(thimble) is turned one complete revolution around the
central screw, it moves twenty-five thousands of an inch.
This is how the internal screw of the micrometer is used
as a precision measuring tool.
Figure 5-1: 0-1 inch outside micrometer
Although this class only uses the 0-1 inch outside
micrometer, many other types of micrometers exist,
including inside micrometers, and multi-anvil
micrometers that can measure objects up to 60 inches.
The aircraft industry demands extremely high-quality
measuring tools. They must to be certified by a FRPSDQ\
DSSURYHG Calibration / Certification Lab, which tests and
certifies that the measurements of the tools are correct. High
quality tools will stay accurate and last much longer than
cheaper versions.
Copyright © 2012 Boeing. All rights reserved.
Micrometer
Components
This section section will cover the typical components of
the 0-1 inch micrometer. In most cases, this information
can be applied to other models.
Locate the following features on your micrometer:
Anvil
The anvil is located at the end of the curved arm of the
micrometer. It is a stationary component and provides a
resting place for the material being measured.
Spindle
The spindle is the other component that touches the
material being measured. Turning the thimble moves the
spindle toward or away from the anvil. The 0-1 inch
outside micrometer measures distances between the anvil
and the spindle, up to one inch.
Thimble
Turning the thimble causes the spindle to go in or out. It
has a textured grip so that your fingers will not slip.
Anvil
Material
Spindle
Sleeve
Thimble
Ratchet
Figure 5-2
Copyright © 2012 Boeing. All rights reserved.
Ratchet
Many micrometers have a ratchet. This
device is located on the end of the thimble
and is connected by a slip system. It allows
the thimble to turn without exceeding a
preset pressure between the spindle and
anvil. This prevents you from over­
tightening the micrometer and getting an
inaccurate reading, or possibly damaging the
tool.
To operate the ratchet, tighten the thimble
until the spindle is very close to – but not
touching - the material. Then turn the ratchet
in the same direction until the ratchet slips.
Sleeve
The sleeve has graduations for measuring the
distance between the anvil and the spindle.
Cleaning the
Micrometer
Check to see that the micrometer spindle and anvil are
clean and free of debris. You can slide a piece of paper
between the spindle and anvil to remove any dirt that may
have accumulated on the two surfaces.
Caring for the
Micrometer
Caution: It is very important that the micrometer be
handled carefully. This tool is precision manufactured to
maintain true measurements. Dropping, throwing, or even
putting it down hard can damage this tool and ruin the
calibration. When storing the Micrometer, do not tighten
the spindle down to the anvil.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
1. _________
Label each of the micrometer components on the
illustration below. Then write a brief description of the
function of each component in the space provided.
Material
2. __________
3. ________
5. __________
4. _________
Write a brief description of the functions of each component.
1. ___________________________________________________________
2. ___________________________________________________________
3. ___________________________________________________________
4. ___________________________________________________________
5. ___________________________________________________________
6. How can you clean the spindle and anvil of a Micrometer?
______________________________________________________________
________________________________________________________
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
Answers
1. Anvil
Material
Below are the labeled components of the micrometer as
well as a description of what each component does.
2. Spindle
5. Ratchet
3. Sleeve
4. Thimble
Write of brief description of each component.
1. Anvil: The stationary part that provides a resting place for the material
being measured.
2. Spindle: Turns in and out, adjusting for the dimension of the material
being measured between the anvil and the spindle.
3. Sleeve: Indicates the measurement reading of the distance between the
anvil and the spindle.
4. Thimble: Turns the spindle in and out.
5. Ratchet: Turns the thimble and allows the thimble to stop when the
pressure between the spindle and anvil has reached a preset level.
6. You can clean debris from the anvil and spindle by sliding a piece of paper
between these two parts.
Copyright © 2012 Boeing. All rights reserved.
Reading the
Measurements
Your micrometer measures materials accurately up to
thousandths of an inch (.001”). Some micrometers can
measure accurately in ten thousandths of an inch (.0001”).
Reading Line
(Datum Line)
On the micrometer sleeve, a heavy black line runs parallel
to the centerline (see Figure 5-3). This line, called the
reading line or the datum line, is 1.000 inch long. It is
divided into 40 equal parts, marked by vertical lines. Each
of the vertical lines represents .025 inch (40 X .025 =
1.000”). Every fourth line is longer and is numbered.
These lines indicate tenths of an inch. For example, the
line marked 1 is equal to 0.100 inch, the line marked 2
equals 0.200 inch, etc. These lines are also read ‘one
hundred thousandths’ and ‘two hundred thousandths’.
Thimble
The thimble is also marked with lines (see Figure 5-3). It
is divided into twenty-five equal parts. Each line is
numbered and represents one-thousandths of an inch
(0.001”). A full revolution of the spindle will move the
spindle twenty-five thousandths of an inch closer or
further from the anvil.
Long, numbered lines = .1 (one hundred thousandths)
Short lines = .025 (twenty-five thousandths)
Thimble dimensions
Each line = .001 inch (one thousandth)
Reading Line
Figure 5-3: Graduations on the Micrometer
Copyright © 2012 Boeing. All rights reserved.
Reading a
Micrometer
Reading a micrometer involves the following steps:
1. Place the material between the anvil and the spindle.
Example 1
2. Move the spindle closer to the material by turning the
thimble, then the ratchet, until the material is in contact
with both the spindle and the anvil. Do not over tighten.
3. Determine the measurement:
a) Note the last visible numbered line on the sleeve. This
will indicate how many tenths of an inch are in the
measurement. For example, if the last number visible is
2, note 0.200” (see Figure 5-4).
b) Look to see if any un-numbered lines are visible after
the last number. If so, add 0.025 for each un-numbered
line you see.
We have already noted 0.200” on the sleeve in Figure 5­
4. Now we add 0.025” for each of the lines visible past
the ‘2’. There is only one un-numbered line visible to
the right of the ‘2’, so we add 0.200 and 0.025:
0.200
0.025
0.225
Our reading for Figure 5-4 is 0.225”.
Figure 5-4: Taking a micrometer reading
Copyright © 2012 Boeing. All rights reserved.
Example 2
Refer to Figure 5-5. The last visible number on the
spindle is 4, so we begin the reading by recording 0.400”
Three smaller lines are visible to the right of the ‘4’ line,
so we add 0.025” for each of those lines (3 X 0.025” =
0.075”). Adding 0.075 to 0.400 equals 0.475.
We can make the reading even more accurate by looking
at the numbered lines on the thimble. We find the line on
the thimble that lines up with the reading line on the
spindle, and then we record the number on the thimble
line.
In Figure 5-5 that number is 12, so we add 0.012 to our
previous measurement (0.475) to get a total measurement
of 0.487.
0.475
+0.012
0.487
Figure 5-5: Reading a micrometer thimble.
Copyright © 2012 Boeing. All rights reserved.
One Final Way
to Read the
Scale
An easy way to read a Micrometer is to think of the
numbers as currency – dollars and coins. Count the
numbers on the sleeve as dollars, the un-numbered lines
on the sleeve as quarters, and the lines on the thimble as
cents. Then simply add up the ‘money’ and put a decimal
point instead of a dollar sign in front of the sum.
Reading TenThousandths
To measure ten-thousandths of an inch with the 0-1 inch
outside micrometer, look at the top of the sleeve and
notice the horizontal ten lines that are parallel with the
reading line. These numbered lines make up the vernier
scale. To read this scale:
1. Find the line on the vernier scale that matches up with
a line on the thimble. You may need to get a
magnifying glass to clearly see which lines match.
2. Note the number of the matching thimble line.
3. Add this number, in ten thousandths, to your
micrometer reading.
For example, we have already determined a measurement
of 0.487” from Figure 5-5. Figure 5-6 provides a close-up
view of the same reading. Here we can see that a line on
the vernier scale matches up with the thimble line marked
‘3’.
We record this vernier scale reading as 0.0003” (read as
‘three ten thousands’, or simply ‘three tenths’) and add
that to our reading of 0.487” to get a final measurement of
0.4873”.
0.4870
+0.0003
0.4873
Copyright © 2012 Boeing. All rights reserved.
A line on the vernier scale matches
up with line 3 on the thimble. This
indicates .0003”. Add this number to
your reading.
Figure 5-6: Reading ten-thousandths of an inch on a micrometer.
Summary: Calculating a micrometer reading
Record the last line visible on the sleeve in tenths of
an inch. (If ‘0’, record as 0.000)................................
0.400”
Record each un-numbered line as 0.025”..................
0.075” (0.025” X 3)
Record the number on the thimble where the sleeve
and thimble lines line up............................................
0.012”
Add the three numbers to get the reading...………...
0.487”
Copyright © 2012 Boeing. All rights reserved.
Determining the Before using a micrometer, it is first important to
determine its accuracy:
Accuracy of a
Micrometer
1. First, validate the zero setting by closing the
micrometer and ensuring that the reading is zero. If
the micrometer doesn’t read zero, ask the facilitator
for a replacement micrometer.
2. Next, obtain a gauge block from the facilitator.
3. Place the gauge block between the anvil and the
spindle and turn the ratchet until the spindle is
against the block.
4. Check the reading to see that it matches the known
value of the gauge block.
If the reading does not match the gauge block within
+/- .001, notify your course facilitator.
Measurement accuracy is critical. Determining the
accuracy of a micrometer is easy to do and will help to
ensure that your measurements meet all quality standards.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2
Micrometer Reading Part 2
Circle the correct answer for the following micrometer
readings. Check your answers against the answer key on
the page following these exercises.
1.
a)
b)
c)
d)
0.037
0.303
0.350
0.375
2.
a)
b)
c)
d)
0.088
0.113
0.117
0.138
3.
a)
b)
c)
d)
0.043
0.068
0.093
0.122
4.
a)
b)
c)
d)
0.208
0.233
0.258
0.262
5.
a)
b)
c)
d)
0.041
0.044
0.045
0.091
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2, continued
6.
a) 0.028
b) 0.033
c) 0.037
d) 0.043
7.
a) 0.138
b) 0.163
c) 0.168
d) 0.173
8.
a) 0.025
b) 0.040
c) 0.050
d) 0.055
9.
a) 0.205
b) 0.206
c) 0.207
d) 0.208
10 a) 0.011
b) 0.012
c) 0.016
d) 1.150
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2, continued
11 a) 0.195
b) 0.205
c) 0.230
d) 0.235
12 a) 0.220
b) 0.240
c) 0.245
d) 2.450
13 a) 0.052
b) 0.058
c) 0.062
d) 0.077
14 a) 0.201
b) 0.225
c) 0.230
d) 0.235
15 a) 0.052
b) 0.502
c) 0.548
d) 0.578
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2, continued
16
__________
17
__________
18
__________
19
__________
20
__________
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Skill Check 2, continued
21
__________
22
__________
23
__________
24
__________
25
__________
Copyright © 2012 Boeing. All rights reserved.
Micrometer Reading Part 2
Enter the correct micrometer reading in the space provided. Check your
answers against the answer key on the page following these exercises.
1. ____________________
2. _________________________
3. ___________________
4. _________________________
5. ____________________
6. __________________________
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2
Answers
Below are the answers to the previous exercises. Check
to see how you did. If you missed more than 3, reread the
materials and check the readings again.
Micrometer Readings Part 1
1.
d. 0.375
8.
c. 0.050
15. c. 0.548
22. 0.213
2.
a. 0.088
9.
d. 0.208
16. 0.323
23. 0.300
3.
c. 0.093
10. c. 0.016
17. 0.195
24. 0.183
4.
b. 0.233
11. b. 0.205
18. 0.102
25. 0.141
5.
d. 0.091
12. c. 0245
19. 0.285
6.
d. 0.043
13. a. 0.052
20. a. 0.180
7.
a. 0.138
14. d. 0.235
21. c. 0.118
Micrometer Readings Part 2
1.
.3886
2.
.4982
3.
.2337
4.
.3104
5.
.0984
6.
.3286
Copyright © 2012 Boeing. All rights reserved.
Skill Check 3
During this Skill Check you will use a micrometer to
measure several items commonly found in the classroom.
When you are done measuring these items, check the
answer key on the next page. Your answers may vary
slightly from the answer key, since the dimensions of
these items vary.
1. ____________ Badge (No badge cover included)
2. ____________ Paper (Any page from this Student Guide)
3. ____________ Pencil (Standard #2 pencil)
4. ____________ Hair (From your head)
5. ____________ Belt (This measurement will vary greatly)
6. ____________
Dry erase board marker (from the facilitator)
Copyright © 2012 Boeing. All rights reserved.
Skill Check 3
Answers
Below are typical measurements of the common items
found in a classroom.
1. Badge - 0.107”
2. Paper - 0.0035”
3. Pencil - 0.351” approx
4. Hair - 0.0025 approx
5. Belt – Varies greatly
6. Dry erase board marker – Varies greatly
Copyright © 2012 Boeing. All rights reserved.
Skill Check 4
During this Skill Check you will use a micrometer to
measure 5 items. Be sure to write out your
measurements to four decimal places and record your
answers on the appropriate line.
Large Pin
Liner
1. _________________
Small
Dowel
2. _________________
Plate
3. _________________
Slotted
Bushing
4. _________________
When you have completed this Skill Check, have the facilitator check your
answers. Practice measuring various items until you are comfortable with
using the micrometer.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 4
Answers
Check your numbers with the answers below. If any of
your answers are significantly different, re-measure the
material and check your answer again. Ask the facilitator
for assistance, if needed.
Large Pin
Liner
1. ____.501_________
Small
Dowel
2. ___.187__________
Plate
3. ___.125__________
Slotted
Bushing
4. ____.406_________
Copyright © 2012 Boeing. All rights reserved.
Summary
In this section you were introduced to the Outside
micrometer. You learned that the parts of the Micrometer
include:
• Anvil
• Spindle
• Sleeve
• Thimble
• Ratchet
In this section you also learned how to read a micrometer
to the nearest ten-thousandth of an inch. You were given
several examples of micrometer settings and asked to
record your readings. You were then given several items
to measure.
If you are now comfortable with using the outside
micrometer, proceed to the next section. Otherwise,
review the material, and ask your facilitator for any
needed assistance.
Copyright © 2012 Boeing. All rights reserved.
S
E C T I O N
Introduction
5: B
A L L
G
A U G E S
Ball gauges are not true precision measuring tool, but are
used in conjunction with precision measuring tools, such as
micrometers or calipers.
This section will explain how ball gauges work and their
common uses.
Section
Objective
The student will be able to take an accurate measurement
with a ball gauge and micrometer.
Skill Check
At the end of this section, the student will be expected to
properly use ball gauges to obtain accurate measurements.
Resources
Copyright © 2012 Boeing. All rights reserved.
• Ball gauge set
• Outside 0-1 inch micrometer
Ball gauges are most commonly used with other pieces of
precision measurement equipment such as micrometers or
Using Ball
calipers. They are used for taking measurements of .125” to
Gauges with
a Micrometer .500” diameter holes. Although not true “calibrated” tools
(tools that have been certified for accuracy by aQDSSURYHG
or Caliper
certification lab), they should be treated with the same care
afforded other precision measuring equipment.
Ball gauges are used to transfer the measurement of drilled
holes ranging in size from .125” to .500”. They are normally
issued in sets of four gauges that cover this range of
measurements.
At the tip of the ball gauge is a split ball, which has a
tapered cone inside that expands the ball when a knob is
adjusted. Once the ball gauge is expanded to the fit the hole
being measured, it is then removed from the hole and
measured with a micrometer or caliper. These steps are
outlined in greater detail below (see Figure 5-1):
Step 1. Select a ball gauge that is within the range of the
hole to be measured.
Step 2. Insert the split ball end of the gauge into the hole
and gently turn the adjustment knob to expand the ball until
the ball makes contact with the sides of the hole.
Step 3. Rotate the gauge at least ninety degrees to
determine if the hole is out of round. If the sides of the split
ball do not continually contact the sides of the hole as the
gauge is rotated, the hole is either out of round or angled.
Step 4. Remove the Ball Gauge from the hole, being careful
not to change the setting.
Step 5. Measure the widest diameter of the split ball with a
micrometer or caliper and record the measurement.
Copyright © 2012 Boeing. All rights reserved.
Ball Gauges
Adjustment Knob
Split Ball
Tapered Cone
Figure 5-1: Measuring a hole with a ball gauge.
Note: When storing ball gauges, be sure to reset the split
ball to its minimum diameter.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
For each question, select the correct answer from the list.
Check your answers with the key on the next page.
1. Ball Gauges are most often used to measure holes
that are within which diameter range?
a)
b)
c)
d)
.125 to .500 inches
.125 to 1.00 inches
.250 to .750 inches
1.00 to 5.00 inches
2. To determine if a hole is out of round or angled, the
ball gauge should be rotated in the hole at least:
a)
b)
c)
d)
30 degrees.
60 degrees.
90 degrees.
180 degrees.
3. Ball gauges can be used in conjunction with
what precision measuring tools?
a)
b)
c)
d)
Micrometers
Calipers
Steel Rulers
Both a & b
5. If the micrometer you are using has a ratchet
on the thimble, you should always use it.
a ) True
b) False
Copyright © 2012 Boeing. All rights reserved.
Skill Check 1
Answers
Check to see how you did on the previous Skill Check. If
you missed any of the questions, return to the information in
this section and review the material.
1. (a) .125 & .500 inches
2. (c) 90 degrees
3. (d) Both a & b
4.
Copyright © 2012 Boeing. All rights reserved.
False
Skill Check
2
Locate the step block in your materials kit and measure the
holes indicated in Figure 5-2 to the nearest thousandths of
an inch (.001”). Record your readings in the spaces
provided. When you have finished, check your answers with
the answer key on the next page.
a.
b.
c.
d.
e.
f.
Copyright © 2012 Boeing. All rights reserved.
Skill Check 2
Answers
Check to see how you did on the previous Skill Check. If
your answers are significantly different than the ones on this
answer key, review this section and measure the holes again.
Ask your facilitator for assistance, if needed.
a. .187
b. .444
c. .156
d. .414
e. .379
f. .315
Congratulations! You have completed the self-paced
portion of Precision Measuring Tools- Basic. You are now
ready to take the Final Test.
Please review this material until you are comfortable with
each section. Refer any questions to the facilitator.
When you are ready for the Final Test, ask the facilitator for
the test booklet. This is a closed book test.
Copyright © 2012 Boeing. All rights reserved.