Question

Which of the following is true for precision polygons?

(a) It is not possible to make a full calibration of the rotary table with one polygon

(b) Correction factor is applicable for reference to the exact centering

(c) Reflecting surfaces should be within 6 to 7 seconds of nominal angle

(d) Correction factor is not applicable when the centre of the mirror is used in calibration

I have been asked this question in class test.

The origin of the question is Precision Polygons in portion Angular Measurement and Circular Division of Engineering Metrology

Answer 1

The correct choice is (a) It is not possible to make a full calibration of the rotary table with one polygon

Best explanation: It is not possible to make a full calibration of the rotary table with only one polygon because of the limited sides. Thus all the lines of the circular scale of an optical rotary table are not inspected for error.