To Measure the Taper Angle of a Shallow Circular Groove (Metrology)

9.12.
It is actually very difficult to measure the internal angle of a shallow circular groove by any method. The method proposed below requires the use of two small balls of equal size and two large balls of equal size and slip gauges. First the small balls are placed in the hole and the slip gauges of maximum length inserted in between the balls. The small balls are removed and large balls inserted and again space between the balls filled up by slip gauges of maximum length. Let us assume that the diameters of the balls are dx and d2, and length of slip gauges in each case is li and l2 respectively. Let the angle of taper be A.
In Fig. 9.13, 0\ and Q2 represent the centres of two balls in two different positions.

Fig. 9.13