# Engineering Metrology Questions and Answers – Alignment Tests on Lathe

This set of Engineering Metrology Multiple Choice Questions & Answers (MCQs) focuses on “Alignment Tests on Lathe”.

1. What is the purpose of locating cylinder in the test of the true running of the main spindle?
a) To locate the chuck
b) To locate the main spindle
c) To locate the feeler
d) To level the machine

Explanation: Locating cylinder is provided to locate the face plate or chuck. Threads get worn out soon thus, locating surface can not be threaded one. Locating surface should be cylindrical and must run truly.

2. In what direction the parallelism of the main spindle to saddle movement is checked?
a) Vertical direction
b) Horizontal direction
c) Both vertical and horizontal direction
d) At an angle

Explanation: Parallelism of the main spindle to saddle movement is checked in both vertical and horizontal direction. In this method, mandrel is used and this mandrel should be so proportioned that its overhang does not produce sag.

3. What is axial play?
a) Freedom of spindle movement in axial direction
b) Freedom of spindle movement perpendicular to axial direction
c) Freedom of spindle movement in direction of cutting forces
d)Freedom of spindle movement in horizontal direction

Explanation: Meaning of axial play is the indispensable freedom of movement of spindle in the axial direction to prevent it from seizing by heating. It is different from axial slip. Axial slip is the axial movement of spindle which follows the same pattern.

4. What will happen if an axial play is not provided to the spindle?
a) It will try to expand
b) It will try to bend
c) It will shrink in some time
d) It will show fracture

Explanation: If axial play is not allowed, it would try to bend. Thus there will be no adverse effect of axial play if the direction of cutting forces remains constant or same. If this direction of cutting force changes, there would be some error introduced due to axial movement of spindle.

5. In leveling of machine, which direction is more important in horizontal plane?
a) Longitudinal
b) Transverse
c) Both longitudinal and transverse
d) Both longitudinal and transverse direction is not important

Explanation: Both longitudinal and transverse directions are equally important in horizontal plane. It will produce a simple bend and undesirable stresses; if any long lathe bed is not installed truly horizontal then there will be a deflection in bed.

6. What is the effect of axial slip in screw cutting?
a) Pitch will not be uniform
b) Pitch will be uniform
c) Pitch will be short
d) Pitch will be high

Explanation: Due to the axial slip, the pitch will not be uniform in the case of screw cutting. It is due to periodic movement of the spindle. However this is not of so much importance while turning.

7. Which of the following is done for testing the true running of headstock centre?
a) Feeler of dial indicator is pressed perpendicular to the taper surface
b) Feeler of dial indicator is pressed parallel to the taper surface of cent
c) Feeler of dial indicator is pressed at acute angle to the taper surface of cent
d) Feeler of dial indicator is pressed at obtuse angle to the taper surface of cent

Explanation: For testing this error of true running of headstock centre, the feeler of the dial indicator is pressed perpendicular to the centre taper surface, and the spindle is then rotated. The deviation which is indicated by the dial gauge gives the trueness of the centre.

8. Which type of surface is produced in case of deviation from parallelism of spindle axis from bed in vertical axis?
a) Tapered
b) Straight
d) Hyperboloid

Explanation: A hyperboloid surface is produced due to any type of deviation from parallelism of axis of spindle from bed in the vertical axis. For this test, a mandrel is fitted in the taper socket of the spindle.

9. Which of the following is not used in testing the pitch accuracy of lead screw?
a) A negative stop
b) Slip gauge
c) Length bars
d) Dial gauge

Explanation: Test for pitch accuracy of the lead screw is performed by fixing a positive stop on the lathe bed. Against the stop, the length bars and slip gauges can be located. On the carriage, indicator is mounted and first it makes contact against the length (calculated) of slip gauges.

10. What is the permissible error in working accuracy of cylindrical turning when a job is held between centers when a practical test is performed?
a) 0.02mm/100 mm
b) 0.01mm/100mm
c) 0.02mm/300 mm
d) 0.01mm/300 mm

Explanation: Working accuracy of machine facing is a permissible error of 0.02 mm over the diameter of test work piece, which is taken as 300 mm for swing over bed of upto 500 mm, and 400 mm for swing over 500 mm. Hence the permissible error is 0.02 mm/300 mm.

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