Heat Exchanger, Coil & Radiator Manufacturing calculator

Header Drilling Rate Calculator

Use this calculator to measure drilling progress or quality on headers, manifolds, and tube sheets. It turns drilled or affected holes and total required holes into a percent that can be compared with a target on the production board.

What this calculator does

  • Calculate header drilling completion or defect rate from drilled holes, total required holes, and a target rate for heat exchanger headers and manifolds.
  • Use it when drilled tube holes, baffle holes, manifold ports, or header plates need a quick progress or quality check against the job target.
  • Calculates a drilling rate and target gap for header plates, manifolds, or tube sheets.

Formula used

  • Header drilling rate = drilled or accepted holes รท total header holes required
  • Gap to target = target drilling rate - calculated drilling rate

Inputs explained

  • Drilled or accepted holes: undefined
  • Total header holes required: undefined
  • Target drilling rate: undefined

How to use the result

  • Use it for shift reporting, first-article checks, machining cell boards, or quality reviews where hole completion or acceptance rate matters.
  • It does not evaluate hole position, burrs, ovality, surface finish, or tube fit. Use inspection data for those quality characteristics.

Common questions

  • Can this track completion and quality? Yes. Use drilled holes for completion rate, or accepted holes for quality rate. Keep the definition consistent across the shift or report.
  • What should total header holes include? Include the holes required by the current drawing revision for the header, manifold, or tube sheet being reviewed.
  • How should the gap to target be used? Use the gap to decide whether machining needs recovery time, added inspection, tooling adjustment, or help before downstream tube insertion waits.
  • When is this not enough for quality approval? It is not enough when hole diameter, location, burr condition, tube fit, or leak risk must be verified against the print or control plan.

Last reviewed 2026-05-12.