Torque (\( T = \frac{\pi \cdot S_d \cdot (D_o^4 - D_i^4)}{16 \cdot D_o} \)):

Where:

• \( T \) is the torque, in inch-pounds (in-lb).
• \( D_o \) is the outer diameter, in inches.
• \( D_i \) is the inner diameter, in inches.
• \( S_d \) is the design stress, 6000 psi.