Welding & Fabrication worked example

Assembly Fit-Up Time at 22% crane, jig, and squaring allowance: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop crane, jig, and squaring allowance to 22%, then walk the calculation through step by step. Estimate weld assembly fit-up time from number of fit-up features, features per minute, and a handling allowance.

The inputs for this scenario

  • Fit-up features to gauge and clamp: 18 features (held at the documented default)
  • Features fit per minute: 2 features / min (held at the documented default)
  • Crane, jig, and squaring allowance: 22 % (the input this scenario stresses; the baseline uses 30)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base assembly fit-up time = fit-up features to gauge and clamp รท features fit per minute.
  • Required assembly fit-up time works out to 10.98 min at these inputs, and this is the headline figure for the scenario.
  • Base assembly fit-up time works out to 9 min at these inputs.
  • Crane, jig, and squaring allowance works out to 22 % at these inputs.
  • Features fit per minute works out to 2 pieces / min at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where crane, jig, and squaring allowance sits at 30% and the headline result is 11.7 min, this scenario comes in 6.15% below the baseline at 10.98 min.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to crane, jig, and squaring allowance, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes a steady fit rate across all features; a few awkward or out-of-position joints can take far longer than the average, so complex weldments need the rate tuned to the hardest features, not the easiest.

Results at a glance

  • Required assembly fit-up time: 10.98 min (headline result)
  • Base assembly fit-up time: 9 min
  • Crane, jig, and squaring allowance: 22 %
  • Features fit per minute: 2 pieces / min

Run it with your numbers

  • To rerun this with your own numbers, open the live Assembly Fit-Up Time calculator, set crane, jig, and squaring allowance to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.