JNTU Question Papers-III-B-Tech-Metro-logy Supplementary Examinations-Aug/Sep 2008

JNTU III B.Tech Supplementary Examinations, Aug/Sep 2008


(Mechanical Engineering)



1. (a) Explain the terms: Limits (upper & lower)of tolerance and fit. Sketch the conventional diagram to represent these terms for a shaft and a hole.

(b) For each of the following shaft and hole pair, calculate shaft tolerance, hole tolerance and analyze whether the pair is

i. Clearance fit

ii. Transition fit

iii. Interference fit.

Pair 1: Hole:- 30+0.02+0.00mm Shaft:- 30?0.04+0.005mm

Pair 2: Hole:- 30+0.06+0.00mm Shaft:- 30?0.03+0.05mm

Pair 3: Hole:- 30+0.05+0.00mm Shaft:- 30+0.08+0.05mm

Sketch the three fits on the same zero line.


2. (a) Discuss the advantages of digital measuring instruments over others. What are progressive errors in micrometers?

(b) Describe the uses and advantages of dial indicators.


3. Discuss various methods of taper measurement of plug and ring gauges.


4. (a) Discuss the applicability of different allowances in design of gauges .

(b) Design and sketch the ‘workshop gauge’, ‘inspection gauge’ and general type of ‘GO and NO GO’ plug gauges for checking holes of 50+0.02?0.001 mm. Assume wear allowance is 10% of gauge tolerance.


5. (a) Explain with a sketch the working of Microptic Auto Collimator .

(b) Elucidate the working principle of optical projector and optical flats.


6. (a) What are various orders of geometrical irregularities on surfaces ? How these are classified?

(b) Describe with a neat sketch the construction , principle and operation of Tomlinson surface meter.


7. (a) What are the advantages, uses and disadvantages of electrical comparators.

(b) Explain the following alignment tests on lathe:

i. True running of locating cylinder of main spindle.

ii. True running of taper socket in main spindle.


8. (a) Elucidate various methods of measuring

i. Thread form

ii. Thread angle by vernier protractor.

(b) Explicate gear metrology of spur gears with reference to Tooth thickness by chordal thickness method.

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