Trapezoidal thread
 Number of thread starts
 Yield strength screw MPa
 Axial load 103 N
 Stroke length 10-3 m
 Nut length 10-3 m
 Specific wear rate 10-15 m2/N
 Ratio of wear depth / 0.5P
 Coefficient of friction
 pitch P 10-3 m
 pitch diameter d2=d-0.5P 10-3 m
 root diameter d3=d-2h3 10-3 m
 thread height H1=0.5P 10-3 m
 tensile stress area At = π/4 d33 10-6 m2
 tensile stress σt = F/At MPa
 torsional stress τ = T/Wp ;  Wp= π/16 d3 MPa
 equivalent stress σe = (σm2 + 3τ2)½ MPa
 safety factor Sv = Rp0.2 / σe >1
 thread support area A1 10-6 m2
 total tightening torque T+ Nm
 loaded unscrew torque T- Nm
 screw efficiency %
 contact pressure p thread MPa
 total sliding distance s=h/(k p) 103 m
 sliding distance single move s1=π d2 Lstroke / P m
 number of moves Ln=s/s1