This set of Engineering Metrology Multiple Choice Questions & Answers (MCQs) focuses on “Sine Principle and Sine Bars”.
1. Up to which angle sine bars can measure the angles?
a) 45 degree
b) 60 degree
c) 90 degree
d) 120 degree
Explanation: The sine bars become impractical and inaccurate as the angle exceeds 45° because the bar is physically clumsy to hold in that position and even a slight error of the sine bar can cause large angular errors after this angle.
2. What is the permissible tolerance on flatness of side faces of sine bars of 100 mm as per IS 5359-1969?
a) 0.001 mm
b) 0.005 mm
c) 0.01 mm
d) 0.05 mm
Explanation: As per IS 5359-1969, the flatness of side faces of sine bars of size 100 mm is 0.005 mm and the tolerances of squareness for side faces to upper face and parallelism of side faces to the roller axes are 0.003/25 mm and 0.01/25 mm respectively.
3. Which of the following is not used in making of sine bars?
a) High carbon
b) High chromium
c) Corrosion resistant steel
Explanation: Sine bars are used to measure angles accurately or locating any work to a specified angle within a close limit. Sine bars are made from high chromium, high carbon, corrosion resistant steel, ground, hardened and stabilised.
4. Which of the distance of the axes of two cylinders of sine bar?
a) 20 inches
b) 50 inches
c) 5 inches
d) 25 inches
Explanation: In British system, the distance between the axes of the two cylinders is 10 or 5 inches, and in metric system the distance between axes of cylinders is 100, 200 and 300 millimeter.
5. Which of the following is incorrect regarding sine bars?
a) Sine bar is itself a complete measuring instrument
b) Some holes are drilled in the body
c) It can be used to locate any work to a given angle
d) It is capable of self generation
Explanation: The sine bar is itself not a complete instrument or complete measuring instrument. Another datum like surface plates are needed. Some holes are drilled in the bar body. It is to facilitate handling and reduce the weight.
6. What is the characteristics permissible tolerance flatness of upper and lower surface of 100mm sine bar I.S. 5359—1969?
Explanation: The permissible tolerance of flatness of upper and lower surfaces of sine bars is 0.001 mm and the tolerance for parallelism of upper and lower surfaces with respect to datum surface is also 0.001 mm.
7. Which of the following is true for the given statements about sine bars?
Statement 1: Grade A sine bars are less accurate than grade B.
Statement 2: Grade B sine bars are accurate up to 0.01 mm/m of length.
a) T, F
b) T, T
c) F, T
d) F, F
Explanation: Sine bars are graded as of A or B grade depending upon the accuracy of the centre distance. B grade of sine bars are accurate up to 0.02 mm per m of length but B grade is less accurate than A grade. A grade sine bars are accurate up to 0.01 mm per m of length.
8. What is the parallelism tolerance of end faces of axes of rollers in sine bar according to British Standards?
a) 0.013mm per 50mm
b) 0.01mm per 25mm
c) 0.013mm per 25mm
d) 0.13mm per 25mm
Explanation: According to British standard, parallelism tolerance of end faces to the axis of the hinge roller is within 0.013 mm/ 25 mm and the accuracy of distance between rollers axes is 0.0025, 0.005 and 0.008 mm for 100 mm, 200 mm and 300 mm bars.
9. What is sine centre?
a) Centre of sine bar
b) Sine bar with block holding centres
c) Sine bar with hole in centre
d) Sine bar with hollow rod in centre
Explanation: A sine bar with block holding centres is known as sine centre. It can be rigidly clamped and adjusted in any position. Sine centres can be used for inspection of the conical objects between centres.
10. As per IS 5359-1969, what is the permissible tolerance on mean diameter of the rollers in 100mm sine bars?
a) 0.005 mm
b) 0.001 mm
c) 0.002 mm
d) 0.01 mm
Explanation: As per IS 5359-1969, the permissible tolerances for mean diameters of rollers and distance between roller axes are 0.002 mm and ±0.03 mm respectively for sine bars of size 100 mm.
11. Which of the following is true for sine table?
a) Sine table is most convenient for the light workpieces
b) Procedure of setting angle is not same as sine bars
c) Table may be safely swung from 0 to 90 degrees
d) Error caused by clamping mechanism is very large
Explanation: Sine table is the development of the sine bar. It is the most accurate and convenient design for heavy workpieces. The principle of setting sine table at any angle is same as for sine bars.
12. Upto which inclination sine centres can be used?
a) 45 degree
b) 90 degree
c) 120 degree
d) 60 degree
Explanation: These are used up to 60 degree angle. Rollers are clamped firmly to the body. Sine centre is a very useful device for testing the conical work centered. The principle of setting sine centre is same as of sine table.
Sanfoundry Global Education & Learning Series – Engineering Metrology.
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