Angle measurement by using Sine Bar.pptx

Angular Measurement, Sine Bar

1. 1 Prepared by, Mr. S. B. Kamble Department of Mechanical Engineering Sharad Institute of Technology, College of Engineering, Yadrav Sine Bar Subject – Metrology and Quality Control

2. Sine Bar Working Principle Working Process Merits and Demerits

3. Sine Bar A precision angle measuring instrument used along with slip gauges.

4. Working Principle of Sine Bar The principle of operation of the sine bar is based upon the application of trigonometry. Fig. (1) Fig. (2) Sin(Ɵ)= (h/L) In a right angle triangle ABC shown in Fig 2 the ratio of the length BC (perpendicular) to that of the length AB (hypotenuse) is referred to as the sine of the angle θ.

5. Surface Plate Slip Gauge Dial Indicator 1 st Position 2 nd Position Angle Measurement by using Sine Bar Finding the approximate angle by using Bevel Protractor . Ɵ appro 2. Using Ɵ appro find the value of h appro h appro h appro = ( Sin(Ɵ) X L) 3. Selecting proper values of slip gauges from slip gauge set. 4. Repeat the process till getting h exact hexact

6. Angle Measurement by using Sine Bar Ɵ exact = Sin -1 ( h exact /L) 5. Finding the Ɵ exact Ɵ exact

7. Angle Measurement by using Sine Bar (For Large Work-piece)

8. Merits of Sine Bar It is easily available. It is precise and accurate angle measuring device. It is simple in design and construction.

9. Demerits of Sine Bar Slight errors of the sine bar cause larger angular errors. It is fairly reliable at angles less than 15 but become increasingly inaccurate as the angle increases. It is impractical to use sine bar for angle above 45. It is difficult to handle and position the slip gauges. The sine bar is physically clumsy to hold in position. The application is limited for a fixed center distance between two rollers.