Third Step:
On putting the values of T1 and T2 in Eq. (8), we get
750 = B /(78.889)1/n . . . (E1)
11.2 = B/(128.07)1/n . . . (E2)
Divide first one (E1) by second (E2),
![2396_Third Step.png](https://www.expertsmind.com/../CMSImages/2396_Third Step.png)
or, (1.62)1/ n = 66.845
∴ 1/ n = 8.71
From Eq. (E1),
![845_Third Step1.png](https://www.expertsmind.com/../CMSImages/845_Third Step1.png)
B = 2.53 × 1019
Putting these values in Eq. (12), we get,
![2032_Third Step4.png](https://www.expertsmind.com/CMSImages/2032_Third%20Step4.png)
= 2.05 × 1017
Vopt = 97.18 m/min
After having obtained the optimum cutting speed, the corresponding spindle speed
(N3) can be obtained as follows :
N3 = Vopt / π = 97.18/ π × 0.0762
N3 = 405.95
∴ N3 = 406