Should You Buy an Extra Sheet of Plywood?

What the benchmark tests

Every project is packed three times on a nominal 96 × 48 inch sheet with a 1/8 inch kerf and rotation allowed. The baseline contains only the source cut list. The first reserve strategy duplicates one unit of the largest-area part. The second duplicates one unit from every named part line. These are explicit replacement-capacity tests, not a hidden percentage added to the final total.

The largest-part strategy increased the estimate for 21 of 75 projects. The one-of-each strategy increased it for 40 projects. A “no change” result means those added rectangles fit within the same heuristic sheet count; it does not prove that the required offcut shapes survive the real cutting sequence.

Project-level sheet-count thresholds

The table shows modeled purchase pressure, not a recommendation to buy exactly the displayed quantity. Follow each project link to inspect its actual parts and assumptions.

How to choose a real contingency

1. Identify parts that are expensive, visible, grain-matched, difficult to machine, or impossible to replace from a narrow remnant.
2. Record usable stock already on hand and exclude offcuts whose material, face, thickness, or dimensions are not verified.
3. Add concrete replacement rectangles to the released layout instead of applying an unexplained blanket percentage.
4. Compare the extra-sheet threshold with supplier lead time, minimum order, return policy, storage, and the cost of a delayed remake.
5. Preserve the decision in the purchase reconciliation and review what was actually consumed at project closeout.

Use the purchase-order reconciliation workflow to document buying units and the yield-variance closeout to compare the released plan with completed production.

What this dataset does not measure

This is modeled reserve capacity, not observed remake frequency, a claim about average shop waste, or actual-versus-planned customer data. The inputs come from WoodCutTool planning examples. The model does not assign defect probability, predict operator errors, inspect real panels, preserve a shop cutting sequence, prove a globally optimal layout, or value delivery delays and unused stock.

Real contingency should reflect the current material, face matching, defects, process capability, replacement lead time, and project risk. Verify the received sheet size and final rectangles in the plywood cut calculator, then save the reviewed project in CutList.

Method and reproducibility

The generator expands part quantities, adds only the rectangles declared by the selected strategy, sorts all pieces deterministically, and runs method woodcuttool-maxrects-v1. Every CSV row includes the original and reserve areas, estimated baseline and contingency sheets, rejected-piece count, completion flag, and source template URL. Re-running the published inputs with the same method version produces the same comparison.