A milling machine has the following two index plates... It is proposed to mill a spur gear of 28 teeth using simple indexing method. Which one of the following combinations of index plate and number of revolutions is correct?
- A. Plate I:1 revolution and 9 holes in 18 hole circles
- B. Plate 2:1 revolution and 9 holes in 21 hole circles
- C. Plate 2:1 revolution and 9 holes in 33 hole circles
- D. Plate I:1 revolution and 9 holes in 15 hole circles
Answer: B. Plate 2:1 revolution and 9 holes in 21 hole circles
Explanation: Indexing = 40/N = 40/28 = 10/7 = 1 + 3/7 = 1 + 9/21. Needs 21 hole circle (Plate 2).