This set of Tough Engineering Metrology Questions and Answers focuses on “General Care of Dial Gauges”.
1. Which of the following statement is true for dial indicators?
a) It can be used as a direct measuring instrument
b) It can only be used as a comparator
c) There is no effect on accuracy if the surface of contact point worn out
d) Test for repeatability is done only once at the starting
Explanation: Dial gauges are only used as comparators and should not be used as direct measuring instruments. It provides only relative measurement. These are used to check consistency and accuracy in manufacturing processes.
2. What will happen if plunger lifting lever released suddenly?
a) Break the plunger
b) Lever will break
c) No effect
d) Distort rack teeth
Explanation: When the plunger lifting lever raised to allow work to be inserted under the contact point, then after completing this it must be released slowly. Sudden release will distort the rack teeth.
3. Which of the following is true for plunger used in dial indicator?
a) It should never be greased or oil
b) It should be greased monthly
c) It should be oil or greased after every use
d) It should be oiled weekly
Explanation: Oiling and greasing are not desirable in plunger of dial indicator. Oiling of plunger will only result in picking up of dust and sticking. The plunger should never be greased or oiled.
4. When does the back mounting used in dial indicators?
a) When space is limited and positive clamping is not required
b) When space is more and positive clamping is required
c) Space is limited and positive clamping is required
d) Space is more and positive clamping is not required
Explanation: A dial indicator could be mounted either by the back or by the stem. Back mounting of dial indicator provides more positive clamping. It is preferred where fixture design mount permits adjustment and space is limited.
5. Which of the following is not true about the clamping force and clamping of dial indicators?
a) Too great clamping force may jam the plunger
b) Clamp should be loose in case of back lug
c) Tight clamp will always cause slip
d) Steel stem are best for clamping
Explanation: If the dial gauge is clamped by the steel stem, then a great a clamping force will cause the jamming of plunger in the stem. The fixture hole must be smooth and true to avoid distortion, locking and binding of stem in it.
6. Which of the following is not true for contact points used in dial indicators?
a) These are generally blackened
b) Made of hardened steel
c) General purpose contact point is of square form
d) Contact end is polished
Explanation: The contact points are made of hardened steel and blackened to avoid rusting. To prevent scratching of workpiece, the contact end is polished. The general purpose contact point is of spherical shape.
7. What is the accuracy of dial indication for 2.3 turns?
a) Within ±1 graduation
b) Within ±0.1 graduation
c) Within ±2 graduations
d) Within ±0.2 graduations
Explanation: The dial indicator should be accurate to within ±1 graduation with 2.3 turns, that is the variation of the actual object size with the setting master is displayed by the pointer position with a maximum error of ± 1 graduation, at any position within 2.3 turns.
8. Which of the following is true for flat surface of flat contacts in dial gauges?
a) Should be parallel to the plunger
b) Should be truly square to the measuring surface of fixture
c) Should be square to the plunger
d) Should be perpendicular to the measuring surface of plunger
Explanation: If contact points of dial gauge are worn, then it should be replaced as early as possible. The surface of flat contacts should be square truly to the plunger and for accurate reading should be parallel to the measuring surface of the fixture.
Sanfoundry Global Education & Learning Series – Engineering Metrology.
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