Heat Exchanger, Coil & Radiator Manufacturing worked example

Header Drilling Rate at 99% target drilling rate: a worked example

This scenario runs the header drilling rate calculation on the strong side: 99% target drilling rate, with every other input held at its documented default. Use it when drilled tube holes, baffle holes, manifold ports, or header plates need a quick progress or quality check against the job target.

The inputs for this scenario

  • Drilled or accepted holes: 8 holes (unchanged)
  • Total header holes required: 250 holes (unchanged)
  • Target drilling rate: 99 % (raised for this scenario; the documented default is 95)

Working through the calculation

  • Applying the documented formula (Header drilling rate = drilled or accepted holes รท total header holes required) to the inputs above produces each figure below.
  • At this operating point the engine returns 3.2 % for header drilling rate, the number this scenario is built around.
  • At this operating point the engine returns 95.8 points for gap to drilling target.
  • At this operating point the engine returns 8 count for drilled or accepted holes.
  • At this operating point the engine returns 250 count for total header holes.

How this compares with the baseline

  • Against the tool's baseline example, where target drilling rate sits at 95% and the headline result is 3.2 %, this scenario lands almost exactly on the baseline at 3.2 %.
  • Use it to track header drilling progress mid-run, gate a header to expansion, or spot a station falling behind its completion target. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.

Results at a glance

  • Header drilling rate: 3.2 % (headline result)
  • Gap to drilling target: 95.8 points
  • Drilled or accepted holes: 8 count
  • Total header holes: 250 count

Run it with your numbers

  • Every input above is editable in the live Header Drilling Rate calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.