Question

Which of the following is true for the measurement of small tapers by balls?

(a) Weight of the ball cause no effect on the accuracy of reading

(b) Measuring pressure exerted can cause axial movement

(c) Measuring pressure exerted cause no effect on the accuracy of reading

(d) Accuracy of small taper measurement is same as large taper

This question was posed to me in an online interview.

This intriguing question comes from Check the Angle of a Tapered Hole in chapter Miscellaneous Measurements (EM) of Engineering Metrology

Answer 1

Right choice is (b) Measuring pressure exerted can cause axial movement

Explanation: A precaution is needed when the small taper is measured with the help of balls. If the ball is allowed to drop in the hole, it will wedge the taper of the hole. Ball weight and measuring pressure that is exerted over it can cause appreciable axial movement and can give inaccurate readings.