CNC Machining worked example

Drilling Cycle Time at 18% peck, retract, and chip-clearance allowance: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop peck, retract, and chip-clearance allowance to 18%, then walk the calculation through step by step. Estimate drilling cycle time from total drilled depth, feed rate, and allowance for pecking, retracts, spot drilling, or chip clearing.

The inputs for this scenario

  • total drilled depth: 48 in (held at the documented default)
  • drilling feed rate: 16 in / min (held at the documented default)
  • peck, retract, and chip-clearance allowance: 18 % (the input this scenario stresses; the baseline uses 25)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base drilling cycle time = total drilled depth รท drilling feed rate.
  • estimated drilling cycle time works out to 3.54 min at these inputs, and this is the headline figure for the scenario.
  • base drilling cycle time works out to 3 min at these inputs.
  • peck, retract, and chip-clearance allowance works out to 18 % at these inputs.
  • drilling feed rate works out to 16 pieces / min at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where peck, retract, and chip-clearance allowance sits at 25% and the headline result is 3.75 min, this scenario comes in 5.6% below the baseline at 3.54 min.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to peck, retract, and chip-clearance allowance, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It treats peck and chip-clearance time as a flat allowance, so it can misjudge very deep holes where retract count and dwell dominate and the real overhead is nonlinear.

Results at a glance

  • estimated drilling cycle time: 3.54 min (headline result)
  • base drilling cycle time: 3 min
  • peck, retract, and chip-clearance allowance: 18 %
  • drilling feed rate: 16 pieces / min

Run it with your numbers

  • To rerun this with your own numbers, open the live Drilling Cycle Time calculator, set peck, retract, and chip-clearance allowance to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.