CNC Machining worked example

Turning Cycle Time at 14% approach, retract, and turret allowance: a worked example

What does the result look like when approach, retract, and turret allowance reaches 14%? The full calculation is worked below with real intermediate numbers. estimating turning cycle time for quoting, routing, capacity planning, or comparing alternate CNC programs

The inputs for this scenario

  • turning cut length: 36 in (unchanged)
  • turning feed rate: 12 in / min (unchanged)
  • approach, retract, and turret allowance: 14 % (raised for this scenario; the documented default is 12)

Working through the calculation

  • Applying the documented formula (Base turning cycle time = turning cut length รท turning feed rate) to the inputs above produces each figure below.
  • At this operating point the engine returns 3.42 min for estimated turning cycle time, the number this scenario is built around.
  • At this operating point the engine returns 3 min for base turning cycle time.
  • At this operating point the engine returns 14 % for approach, retract, and turret allowance.
  • At this operating point the engine returns 12 pieces / min for turning feed rate.

How this compares with the baseline

  • Against the tool's baseline example, where approach, retract, and turret allowance sits at 12% and the headline result is 3.36 min, this scenario comes in 1.79% above the baseline at 3.42 min.
  • A figure at this level is achievable when approach, retract, and turret allowance is genuinely sustained, not just peaked for a shift. It assumes one constant feed and a single combined cut length, so it underestimates parts with many tool changes, threading passes, or large differences between roughing and finishing feeds.

Results at a glance

  • estimated turning cycle time: 3.42 min (headline result)
  • base turning cycle time: 3 min
  • approach, retract, and turret allowance: 14 %
  • turning feed rate: 12 pieces / min

Run it with your numbers

  • Every input above is editable in the live Turning Cycle Time calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.