JNTU
JNTU B.Tech III ENGINEERING METROLOGY Previous Question Paper (March - 2024 - 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
Compare hole basis system with shaft basis system.
Answer
In the hole basis system, the hole size is kept constant and the shaft size is varied to obtain different fits, which is preferred in industrial practice due to the availability of standard reamers. In the shaft basis system, the shaft size is kept constant and the hole size is varied, which is used primarily when using standard shafting or cold-drawn bars.
Give the classification of fits.
Answer
Fits are classified into three main categories based on the relative position of the tolerance zones of the hole and the shaft:
- Clearance fit: The hole is always larger than the shaft, allowing for relative motion.
- Interference fit: The shaft is always larger than the hole, requiring force for assembly and creating a permanent or semi-permanent joint.
- Transition fit: The tolerance zones overlap, resulting in either a clearance or an interference depending on the actual sizes produced.
What are the limitations of gauges?
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Give the classification of sine bars.
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List the uses of surface plates.
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Explain the principle of interferometry.
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List the reasons for controlling the surface roughness.
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Compare surface roughness and waviness.
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Give the classification of CMMs.
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Define drunken thread.
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Part B
Explain the principal features of the International standard system of limits and fits for plain work.
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Do you think interchangeability reduces number of rejects? Justify your answer.
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The limits shown on a drawing for a mating hole and shaft are 50.046/50.000 for the Hole mm and 50.010/49.971 for the shaft mm. State the type of fit and find the allowance. What is the greatest possible amount of clearance or interference?
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Compare unilateral system and bilateral system of tolerances.
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List out the precautions to be taken while using slip gauges.
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Interpret the Taylor’s principle of gauge design.
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With the help of a neat diagram, explain the construction and working of a bevel protractor.
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Explain the features and uses of position gauges.
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What is a straight edge? Explain how it can be used to measure the straightness.
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Explain the working principle of optical projector. What are the uses and specific applications of optical projector? Explain.
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State the possible causes of each of the various types of irregularities found in surface texture. Explain how surfaces having the same numerical assessment may have different properties and texture.
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Explain the relationship between type of process used to generate a surface and surface roughness obtained.
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Choose a practical method of measuring gear tooth thickness and explain it.
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Explain various alignment tests to be conducted on drilling machines.
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