A drive on a machine tool is to be made by two spiral gears of the same hand and normal pitch of \(12.5 \mathrm{~mm}\). The gears are of equal diameters and centre distance between the shafts is approximately \(134 \mathrm{~mm}\). The angle between the two shafts is \(80^{\circ}\) and speed ratio 1.25 . Calculate

(a) spiral angle of each wheel,

(b) number of teeth on each wheel

(c) efficiency of drive, and

(d) maximum efficiency.

The friction angle is \(6^{\circ}\).