Angular_Measurement.ppt

1. 1
Angular
Measurement
Session 2

2. 2
Angular Measurement
• Circles are divided into 360 equal parts,
each being a degree.
• Each of these degrees can be evenly
divided into 60 equal parts. These parts
are called minutes.
• These minutes can be evenly divided into
60 equal parts. These parts are called
minutes.

3. 3
Angular Measurement
• 1 Circle = 360 Degrees ( 360° )
• 1 Degree ( 1° ) = 1/360th of a Circle
• 1 Degree ( 1°) = 60 Minutes ( 60' )
• 1 Minute ( 1' ) = 1/60th of a Degree
• 1 Minute ( 1') = 60 Seconds ( 60" )
• 1 Second ( 1" ) = 1/60th of a Minute

4. 4
Angular Measurement
• The unit of degree can also be divided
into either decimal or fractional parts and
is referred to as decimal degrees or
fractional degrees respectively.
• 1½ Degree = 1.5 Degree ( 1.5°)
• 87¼ Degrees = 87.25 Degrees ( 87.25° )

5. 5
Angular Measurement
• Minutes and seconds can each be
expressed as decimal or fractional
degrees.
• 1 Minute ( 1' ) = 1/60th of a Degree =
0.01667°
• 1 Second ( 1" ) = 1/60th of a Minute =
0.01667'

6. 6
Angular Measurement
Change 5°25' to decimal degrees
Divide the minutes by 60
Add 0.4167 to 5 = 5.4167°
5°25' = 5.4167°
25 divided by 60 = 0.4167

7. 7
Angular Measurement
Change 27°52'35" to decimal degrees
Divide the seconds by 60, add to minutes
Divide the minutes by 60, add to degrees
27°52'35" = 27.8764°
35 divided by 60 = 0.5833
Added to the 52 minutes, it becomes 52.5833'
52.5833 divided by 60 = .8764
Added to the 27 degrees, it becomes 27.8764°

8. 8
Angular Measurement
Change 47.75° to degrees, minutes,
and seconds
Multiply the decimal portion by 60
This decimal .75 becomes 45 minutes.
Add this to the degrees.
47.75° = 47°45'
75 x 60 = 45
Since there isn't any decimal portion after
the 45, no further work is necessary.

9. 9
Angular Measurement
Change 82.3752° to Degrees, minutes, and
seconds
Multiply the decimal portion by 60
Multiply the decimal minutes by 60
82.3752° = 82°22'30.72"
0.3752 x 60 = 22.512 (the 22 becomes
the minutes) Now add this to the degrees
0.512 x 60 = 30.72 Now add this to the
degrees and minutes to become seconds.
82.3752° = 82°22.512'

10. 10
Angular Measure Tools

11. 11
Angular Measurement
• Most common tools
• Simple Protractor
• Multi-Use Gage
• Combination Set
• Universal bevel protractor
• Sine bar
• Sine plate

12. 12
Protractor

13. 13
Protractor
Whole degree increments

14. 14
Multi-Use Gage
Pre-set positions for
45 and 90 degrees,
59 degree drill point
angle, and whole
degree increments.

15. 15
Multi-Use Gage
Pre-set position for 90 degrees.

16. 16
Multi-Use Gage
Pre-set position for 45 degrees.

17. 17
Multi-Use Gage
Measuring 59 degree drill point angle.

18. 18

19. 19
Combination Set Protractor
Whole degree increments

20. 20
Protractor Head
Whole
degree
increments

21. 21
Protractor
Built-in
Spirit
Level

22. 22
Protractor
Angular
Measure
with
Protract
or Head

23. 23
Transfer-type Protractors

24. 24
• Precision
angles to within
5' (0.083º)
• Consist of base
• Vernier scale
• Protractor dial
• Sliding blade
• Dial clamp nut
Universal Bevel Protractor

25. 25
Vernier Protractor
• Used to measure obtuse angle (90º-180º)
• Acute-angle attachment fastened to
protractor to measure angles less than 90º
• Main scale divided into
two arcs of 180º
• Scale divided into 12
spaces on each side of 0
• If zero on vernier scale
coincides with line on
main: reading in degrees

26. 26
Reading a Vernier
Protractor
• Note number of whole degrees between zero
on main scale and zero on vernier scale
• Proceeding in same direction, note which
vernier line coincides with main scale line
50º
Fourth
• Multiply number by 5' and add to
degrees on protractor dial
4 x 5'= 20'
Reading =
50º 20'

27. 27
Inclinometer

28. 28
Sine Bars
• Used when accuracy of angle must be
checked to less than 5 minutes
• Consists of steel bar with two cylinders
of equal diameter fastened near ends
• Centers of cylinders exactly 90º to edge
• Distance between centers usually 5 or 10
inches and 100 or 200 millimeters.
• Made of stabilized tool hardened steel

29. 29
Sine Bar

30. 30
Sine Bars
• Used on surface plates and any angle by
raising one end of bar with gage blocks
• Made 5 inch or in multiples of 5 or 100
millimeters or multiple of 100
• Distance between lapped cylinders.
• Face accurate to within .00005 in.
in 5 inches or 0.001 mm in 100 mm.

31. 31
Sine Bars

32. 32
Sine Plate