Example lead twice the pitch

Lead is an input. Starts are not looked up.

Worked example

Lifting torque 1.1189 N·m

Lowering torque -0.1683 N·m

Efficiency 56.8979 %

T_R uses sec(alpha) plus collar torque

T_L uses the lowering fraction plus collar torque

(F × Lead) / (2 × pi × T_R) × 100

Efficiency uses the raising torque in the printed equation. A separate lowering efficiency is not calculated.

For these inputs, f x sec(alpha) is not greater than tan(lambda). This page does not turn that comparison into a holding test.

Mean diameter and lead angle

Mean diameter 18 mm

d_m = major - pitch / 2

Lead angle 8.0523 deg

tan(lambda) = Lead / (pi × d_m)

Diameters are converted to meters so newtons give newton-meters. Alpha is the angle you enter. It is not defined as half of 29 or 30 degrees.