angle measurement

ANGLE MEASURING DEVICES

1. VERNIER BEVEL PROTRACTOR

2. SINE BAR

3. ANGLE GUAGES

4. CLINOMETERS

VERNIER BEVEL PROTRACTOR

MOVING BLADE -150-300mm LONG , 13mm WIDE AND 2mm THICK

• Precision angles to within 5' (0.083º)

• Consist of base– Vernier scale– Protractor dial– Sliding blade– Dial clamp nut

Universal Bevel Protractor

13-5

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– Vernier Scale divided into 12

spaces on each side of 0– If zero on vernier scale

coincides with line on main, reading in degrees

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'

USES OF BEVEL PROTRACTOR

Checking inside bevelled face of a ground surface

OPTICAL BEVEL PROTRACTOR

INTRODUCTION TOSINE BAR

SINE BAR USE• The sine bar is used either for very accurate angular measurements or

for locating work at a given angle.• The sine bar is especially useful in measuring or checking angles when

the limit of accuracy is 5 minutes or less

USE OF SINE BAR

1. LOCATING ANY WORK TO A GIVEN ANGLE

2.CHECKING OR MEASURING UNKNOWN ANGLES

3. MEASURING ANGLES FOR LARGE SIZE COMPONENTS

CLINOMETER

A clinometer is a spirit level mounted on a rotary member and the angle of inclination of the rotary member relative to its base is the measurement of the angleon the circular scale

-used for setting inclinable table on jig boring machines and angular work on grinding machines etc.

Disadvantage of levels

• There are four principal disadvantage of levels

1. General ignorance about their proper use and application

2. The time required to settle down3. Their single sensitivity characteristic4. They do not produce any output that can be

used as loading for a measurement system

ANGLE GUAGES

Angle Gauge Blocks permit fast, simple, and accurate measurement of angles.

Made up of Hardened and Stabilized Steel

Push down the sides of the angle blocks on a surface plate to align the sides of the blocks. If the sides are not even

12 piece set

13 piece set