Angular_Measurement.ppt
- 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. 2
- 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 3
- 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° ) 4
- 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' 5
- 6. Angular Measurement Change 5°25' to decimal degrees 6 Divide the minutes by 60 Add 0.4167 to 5 = 5.4167° 5°25' = 5.4167° 25 divided by 60 = 0.4167
- 7. Angular Measurement Change 27°52'35" to decimal degrees 7 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. Angular Measurement Change 47.75° to degrees, minutes, and seconds 8 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. Angular Measurement Change 82.3752° to Degrees, minutes, and seconds 9 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 Different Types Of Measuring Instruments 1. Protractor. 2. Multi-Use Gauge 3. Bevel Protector 4. Sine Bar (Sine Principle). 4. Sine Centre. 5. Angle Gauges. 6. Clinometers. 7. Interferometer, Autocollimator and Optical Flats.
- 11. Protractor 11
- 12. Protractor 12 Whole degree increments
- 13. Multi-Use Gauge 13 Pre-set positions for 45 and 90 degrees, 59 degree drill point angle, and whole degree increments.
- 14. Multi-Use Gauge 14 Pre-set position for 90 degrees.
- 15. Multi-Use Gauge 15 Pre-set position for 45 degrees.
- 16. Multi-Use Gage 16 Measuring 59 degree drill point angle.
- 17. 17
- 18. 18 Bevel Protractor This is probably the simplest instrument for measuring the angle between two faces of the component. It consists of a base plate, an adjustable blade, a Vernier scale and a main scale. Vernier scale contains 24 divisions coinciding with 23 main scale divisions. Least count of the instrument is 5’(minutes).
- 19. Combination Set Protractor 19 Whole degree increments
- 24. Universal Bevel Protractor Precision angles to within 5' (0.083º) Consist of base Vernier scale Protractor dial Sliding blade Dial clamp nut 24
- 25. 25 Diagram showing improved bevel protractor and combinations of sets
- 26. 26 A protractor is a device for measuring the angle between two intersecting lines. The angle is measured in degrees, and a circle is defined as having 360 degrees of identical size. A universal bevel protractor consists of a base plate attached to the main body, and an adjustable blade which is attached to a circular scale containing Vernier scale. The adjustable blade is capable of sliding freely along the groove provided on it and can be clamped at any convenient length. The adjustable blade along with the circular plate containing the vernier scale can rotate freely about the centre of the main scale engraved on the body of the instrument and can be locked in any position with the help of clamping knob. An acute angle attachment is provided for the purpose of measuring angles. The base plate so that it can be laid upon the work and any type of angle can be measured. Measuring Acute Angles Measuring Obtuse Angles Using a protractor with a vernier height gauge 6 Bevel Protractor
- 27. 27 The main component of the bevel protractor is the main scale. The main scale is graduated into four 90-degree components. The main scale is numbered to read from 0 to 90 degrees and then back from 90 degrees to 0. As with other Vernier measuring devices, the Vernier scale of the bevel protractor allows the tool to divide each degree into smaller increments. The Vernier scale is divided into 24 spaces, 12 spaces on either side of the zero (Fig 1). Each space on the Vernier scale is, therefore, one-twelfth of a degree. One-twelfth of a degree is equal to 5 minutes. To read the protractor, note where the zero on the Vernier scale lines up with the degrees on the dial in Figure 10. The degrees are read directly from the main scale. The zero on the Vernier scale is just pass the 85 degree mark. Now, reading in the same direction (counter-clockwise), count, by five, from zero on the Vernier scale to the lines that match up on the dial (Fig 2). Add this number of minutes to the number of whole degrees. The total number of degrees and minutes in Figure 2 would equal 85 degrees and 30 minutes. Fig 1 Fig 2 7
- 28. 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 28
- 29. Reading a Vernier Protractor Note number of whole degrees between zero on main scale and zero on vernier scale 29 • 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'
- 30. 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 30
- 31. Sine Bar 31
- 32. 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. 32
- 33. Sine Bars 33
- 34. 34 Sine centre This is a sine bar with block holding centre which can be adjusted and rigidly clamped in any position. Generally used for inspection of conical objects between centre. These are used up to inclination of 60 degree. Principle used here is same as of the sine bar.
- 35. 35 As slip gauges are built up to give a linear dimension , the angle gauges can be built up to give required angle. They are made of hardened steel and seasoned carefully to ensure permanence of angular accuracy. These gauges are about 3 inch long and 5/8 inch wide with their faces lapped to within 0.0002 mm and angle between the two ends to +/- 2 seconds. All these angle gauges in combination can be added or subtracted thus making a large no. of combinations possible. Angle gauges
- 36. 36 Clinometer The clinometer is used as precision setting tool, to set a tool head or table at specific angle. The clinometer are also used for checking angular, and relief angles on large cutting tools and milling cutter inserts. In clinometer the spirit level is mounted on the rotary member carried in a housing. On the housing, there is a circular scale. The clinometer is mainly used to determine the included angle of two adjacent faces of work piece.
- 37. 37