d0 8.75[mm] "Thread mean diameter"
d1 5.8[mm] "Nominal thread diameter"
p 1.5[mm] Pitch
beta 30[deg] "Semi thread angle"
T 1000[N*mm] "Applied torque"
A p/(pi*d0) "Tangent of the helix angle"
mu 0.15 "Friction coefficient"
W 2*T*(1-mu*A*sec(beta))/(d0*(A+mu*sec(beta))+mu*sec(0.7854)*d1*(1-mu*A*sec(beta))) "Axial preload"
k 1e5[N/m^3] "Spring coefficient"