In: Mechanical Engineering
Calculate the torque requirements for SAE 5.8 Class Bolt having a size of M24 x 3 UNC
The target torque of a bolt
T = k* D * P
Where
K = 0.2
K factor in this formula is always an estimate. The most commonly used bolting K factors arc 0.20 for plain finished bolts, 0.22 for zinc plated bolts, and 0.10 for waxed or highly lubricated bolts.
D = 24 mm = 0.024m
Yield strength = 420 Mpa = F/A
F = 4.2x108 * 0.0004524 = 190003.524 N
P = 0.75* 190003.524 = 142502.643 N
T = 0.2*0.024*142502.643 = 684.01Nm ( max allowed torque)