Welding & Fabrication worked example

Grinding and Finishing Time at 29% disc change, inspection, and break allowance: a worked example

What does the result look like when disc change, inspection, and break allowance reaches 29%? The full calculation is worked below with real intermediate numbers. Use it to estimate post-weld grinding, blending, and polishing time on a weldment so finishing labor does not get under-quoted.

The inputs for this scenario

  • Inches of weld to grind and finish: 120 in (unchanged)
  • Finish inches per minute: 12 in / min (unchanged)
  • Disc change, inspection, and break allowance: 29 % (raised for this scenario; the documented default is 25)

Working through the calculation

  • Applying the documented formula (Base grinding and finishing time = inches of weld to grind and finish รท finish inches per minute) to the inputs above produces each figure below.
  • At this operating point the engine returns 12.9 min for required grinding and finishing time, the number this scenario is built around.
  • At this operating point the engine returns 10 min for base grinding and finishing time.
  • At this operating point the engine returns 29 % for disc change, inspection, and break allowance.
  • At this operating point the engine returns 12 pieces / min for finish inches per minute.

How this compares with the baseline

  • Against the tool's baseline example, where disc change, inspection, and break allowance sits at 25% and the headline result is 12.5 min, this scenario comes in 3.2% above the baseline at 12.9 min.
  • A figure at this level is achievable when disc change, inspection, and break allowance is genuinely sustained, not just peaked for a shift. The linear inches-per-minute rate assumes consistent bead size and finish spec; a step change from a #4 brushed finish to a mirror polish, or grinding out undercut, can double the real rate and break the estimate.

Results at a glance

  • Required grinding and finishing time: 12.9 min (headline result)
  • Base grinding and finishing time: 10 min
  • Disc change, inspection, and break allowance: 29 %
  • Finish inches per minute: 12 pieces / min

Run it with your numbers

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

Last reviewed 2026-05-12.