볼트의 토크와 축력의 관계는 다음 식과 같다.
$T = K F d$
where,
T = wrench torque(N.m, in.lb)
K = constant that depends on the bolt material and size
d = norminal bolt diameter(m, in)
F = axial bolt force(N, lb)
Typical values for K with mild-steel bolts in range 1/4" to 1" :
normal dry : 0.2
nonplated black finish : 0.3
zink-plated : 0.2
slightly lubricated : 0.18
cadmium-plated : 0.16