305 Minimum Diameter of Steel Shaft With Allowable Angle of Twist

$3^\circ \left( \dfrac{\pi}{180^\circ} \right) = \dfrac{12(6)(1000^3)}{\frac{1}{32}\pi d^4 (83\,000)}$

$d = 113.98 \, \text{mm} \,$           answer
 

$\tau_{max} = \dfrac{16T}{\pi d^3} = \dfrac{16(12)(1000^2)}{\pi (113.98^3)}$

$\tau_{max} = 41.27 \, \text{MPa}$           answer