Enter the preload percentage (%), the tensile yield (psi), nominal diameter (in), and the area (in^2) into the calculator to determine the Preload Torque. 

Preload Torque Formula

The following formula is used to calculate the Preload Torque.

Tpl = (y%/100*S*A)*d/12

  • Where Tpl is the Preload Torque (lbf-ft)
  • y% is the preload percentage (%) 
  • S is the tensile yield (psi) 
  • A is the area (in^2) 
  • d is the nominal diameter (in)

How to Calculate Preload Torque?

The following example problems outline how to calculate Preload Torque.

Example Problem #1

  1. First, determine the preload percentage (%). In this example, the preload percentage (%) is determined to be 65 .
  2. Next, determine the tensile yield (psi). For this problem, the tensile yield (psi) is measured to be 20000 .
  3. Next, determine the area (in^2). In this case, the area (in^2) is found to be .25.
  4. Next, determine the diameter. For this problem, this is .50 in.
  5. Finally, calculate the Preload Torque using the formula above: 

Tpl = (y%/100*S*A)*d/12

Inserting the values from above and solving yields: 

Tpl = (65/100*20,000*.25)*.50/12 = 135.41 (lbf-ft)

Example Problem #2

Using the same method as above, determine the variables required by the formula. For this example problem, these are:

preload percentage (%) = 75

tensile yield (psi) = 10000

area (in^2) = .50

diameter (in) = 2

Enter these given values yields: 

Tpl = (75/100*10,000*.50)*2/12 = 625 (lbf-ft)