Advanced Engineering Metrology Questions on “Parallelism, Equidistance and Coincidence”.
1. Which of the following is true for testing parallelism between two trajectories?
a) Dial indicator is attached on a fixed machine component
b) Moving parts are moving in different directions in testing the parallelism
c) The two parts are moved by the same amount
d) Parts are moving together
Answer: c
Clarification: The dial indicator is attached to one of the moving machine components and its feeler rests against a specified point on the other moving part. The two parts are moved together by the same amount in the same direction and the variations in the reading are noted.
2. Which of the following is true for coincidence between two axes?
a) Light weight dial indicator is used
b) Direction of measurement doesn’t varies
c) There is no effect of gravity force
d) Mandrel is used to represent the plane
Answer: a
Clarification: Light weight dial indicator is used in this test. The direction of the measurement varies during rotation in relation to the gravity direction. The sensitivity of the apparatus to the gravity force is taken into account.
3. Which of the following is true to check parallelism between two straight lines formed by the intersection of two planes?
a) V-blocks are used for large distance between two lines
b) No need of V-blocks
c) If there is a small distance between straight lines then use of V-blocks is the most necessary
d) It can be checked only by a straight edge
Answer: a
Clarification: If the distance between two lines is not small or large then the V-blocks are used. V- blocks are covered by a straight edge is used. Check for this is made by spirit level. For small distance there is no need of these.
4. What is the tolerance of parallelism of straight lines?
a) 0.015 on 300 mm
b) 0.15 on 300 mm
c) 0.015 on 600 mm
d) 0.15 on 600 mm
Answer: a
Clarification: Permissible deviations or tolerance of parallelism of two plane surfaces or straight lines is 0.015 mm on 300 mm. Free end of the spindle relative to the table surface is in upward direction only.
5. Which of the following is not true for coincidence?
a) Two axes merged in each other
b) Coincidence and perpendicularity are same
c) One axis extends beyond the other
d) Sometimes coincidence is used with is used with more general meaning of parallelism
Answer: b
Clarification: Two lines or axes are said in alignment or coincident when their distance apart at several points is measured over a specified length and this distance doesn’t exceed a specified value. The measured distance may be located either on the actual lines or on their prolongation.
6. Which of the following is true for measurement of equidistance?
a) Related to distance between two axes
b) Related to distance between two planes
c) Related to distance between reference plane and the axes
d) There is no relation with axes and planes