Fastening, Torque & Joint Assembly worked example

Bolt Preload Estimate at 17% setup, access, and retest allowance: a worked example

Push setup, access, and retest allowance up to 17% and the picture changes. This example computes every intermediate figure at that operating point. Use it when planning preload confirmation, torque-tension checks, ultrasonic bolt measurement, or critical bolted-joint verification workload.

The inputs for this scenario

  • Bolts or joints needing preload verification: 120 joints (unchanged)
  • Verified preload checks per hour: 18 checks / hr (unchanged)
  • Setup, access, and retest allowance: 17 % (raised for this scenario; the documented default is 15)

Working through the calculation

  • Applying the documented formula (Base preload verification time = bolts or joints needing verification รท verified preload checks per hour) to the inputs above produces each figure below.
  • At this operating point the engine returns 7.8 hr for required preload verification hours, the number this scenario is built around.
  • At this operating point the engine returns 6.67 hr for base verification hours.
  • At this operating point the engine returns 17 % for setup/access allowance.
  • At this operating point the engine returns 18 checks / hr for preload verification rate.

How this compares with the baseline

  • Against the tool's baseline example, where setup, access, and retest allowance sits at 15% and the headline result is 7.67 hr, this scenario comes in 1.74% above the baseline at 7.8 hr.
  • It divides the number of joints needing preload verification by your verified check rate, then inflates that base time by a setup, access, and retest allowance to give realistic audit hours. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Required preload verification hours: 7.8 hr (headline result)
  • Base verification hours: 6.67 hr
  • Setup/access allowance: 17 %
  • Preload verification rate: 18 checks / hr

Run it with your numbers

  • Every input above is editable in the live Bolt Preload Estimate calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.