Question

Brown and sharp indexing plates used in indexing will have the following hole circles.
Plate 1 : 15, 16, 17, 18, 19, 20
Plate 2 : 21, 23, 27, 29, 31, 33
Plate 3 : 35, 37, 39, 41, 43, 47, 49
The plates which can be used for producing 23 divisions on the job using simple indexing is

• A. 1 only
• B. 2 only
• C. 2 & 3 only
• D. 1, 2 & 3

Answer 1

The correct option is B 2 only

Crank rotation C.R. $=\frac{40}{N}$
where N = Number of divisions by which the circumference of the job is to be divided.
$=\frac{40}{23}=1\frac{17}{13}\Rightarrow$ Not possible
Therefore, 23 divisions can be done only by using plate 2.