JNTU
JNTU B.Tech III ENGINEERING METROLOGY Previous Question Paper (July/August - 2023 - R13)
Note: i) Question paper consists of Part A, Part B.
ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions.
iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
State the need of precision measurement.
Answer
Precision measurement is essential in modern manufacturing to ensure the interchangeability of components, which allows parts produced in different locations to be assembled without modification. It is also necessary to maintain dimensional accuracy and geometric tolerances, which directly influence the functional performance, reliability, and service life of mechanical systems.
How do you classify Fits?
Answer
Fits are classified based on the relationship between the hole and shaft sizes, which determines the nature of their assembly. They are categorized into three primary types:
- Clearance Fit: A fit where the hole is always larger than the shaft, ensuring a positive clearance between the mating parts. This allows for relative motion, such as in sliding or rotating joints.
- Interference Fit: A fit where the shaft is always larger than the hole, resulting in a negative clearance. This requires force for assembly and is used for permanent or semi-permanent joints, such as press fits.
- Transition Fit: A fit where the tolerance zones of the hole and shaft overlap, potentially resulting in either a clearance or an interference depending on the actual manufactured sizes. This is used for parts requiring accurate location but not necessarily relative motion.
State the advantages of Vernier caliper and micro meter.
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Define the Taylor’s principle of gauge design.
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What are the applications of Laser interferometers?
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What are the applications of straight edges?
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Describe the Rz value, and RMS value methods of qualifying surface roughness.
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What is a Profilometer?
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What is the principle of effective diameter measurement?
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Give the classification of CMMs.
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Part B
What do you understand by geometrical and positional tolerances? How are they specified on a drawing?
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A 50 mm H hole with tolerance grade 7 is to mate 50 mm of shaft of tolerance grade 6. Indicate the fit designation.
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What are the difference between IS 919 and ISO system of limits and fits?
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What is standard gauge? Can it be used to check an interference fit? Why?
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What is the difference between go gauge and no go gauge?
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Explain the working principle of Sine bar and its uses with a sketch.
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What is the classification of slip gauges? Explain the manufacture of slip gauges.
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Explain the working principle of Vernier Bevel protractor with a neat sketch.
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Describe the Tool maker’s microscope with a sketch.
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Describe the fringe formation in an optical flat.
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Explain the construction and working of an Autocollimator.
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Explain the interference method of measuring flatness of surface.
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How is the numerical methods of measurement of surface irregularities?
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Distinguish between roughness and waviness.
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With the help of a neat sketch, explain the Taylor–Hobson talysurf.
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Explain ISI symbols for surface roughness indication.
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How is Taylor’s principle applicable to thread gauging?
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What is the radial runout of a gear? How is it measured?
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With the help of a sketch, explain the principle of working of pneumatic comparators.
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Explain various alignment test conducted on drilling machine.
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