Question

In order to cut 30 T gear, we use No. 4 cutter which is suitable for the range 26 T to 34 T. If helical teeth with helix angle α are to be cut, the size of cutter is given by

1.

(number of teeth)/α

2.

(number of teeth)/cos α

3.

(number of teeth)/(cos α)2

4.

(number of teeth)/(cos α)3

Answer 1

Correct Answer - Option 4 :

(number of teeth)/(cos α)3

Explanation:

For helical gear cutting, the choice of the cutter corresponds to the number of teeth decided by,

\(Z_1 =\frac{{Z}}{{(cosα)^3 }}=\frac{{Number~of~teeth}}{{(cosα)^3}}\)

Z₁ = Number of teeth which should be considered for the choice of cutter (Size of the cutter)

Z = Actual number of teeth on gear to be cut

α = Helix angle

Cutter Number	Cuts Spur gear teeth from
1	2135 teeth to rack
2	55 - 134
3	35 - 54
4	26 - 34
5	21 - 25
6	17 - 20
7	14 - 16
8	12 -13