Fastener Manufacturing & Thread Rolling worked example

Inspection Sample Size at 72% sampling coverage factor: a worked example in fastener manufacturing & thread rolling

Suppose sampling coverage factor falls to 72%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate total fastener inspection samples from planned lots, checks per lot, coverage factor, and accepted sampling yield.

The inputs for this scenario

  • Samples required per inspection point: 13 samples (held at the documented default)
  • Inspection points or lots: 24 points (held at the documented default)
  • Sampling coverage factor: 72 % (the input this scenario stresses; the baseline uses 100)
  • First-pass acceptance factor: 96 % (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Gross inspection samples = samples per inspection point × inspection points or lots.
  • Good output capacity works out to 216 units at these inputs, and this is the headline figure for the scenario.
  • Gross sample checks works out to 312 samples at these inputs.
  • Coverage reduction works out to 87.36 samples at these inputs.
  • Retest or rejection allowance works out to 8.99 samples at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where sampling coverage factor sits at 100% and the headline result is 300 units, this scenario comes in 28% below the baseline at 216 units.
  • It computes planned accepted samples by multiplying samples per inspection point by the number of points or lots, then applying a sampling coverage factor and a first-pass acceptance factor. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Good output capacity: 216 units (headline result)
  • Gross sample checks: 312 samples
  • Coverage reduction: 87.36 samples
  • Retest or rejection allowance: 8.99 samples

Run it with your numbers

  • To rerun this with your own numbers, open the live Inspection Sample Size calculator, set sampling coverage factor to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.