Sheets to buy
—
Shop estimate. Measure your stock and cut a test on scrap.
How to use it
- Set the sheet you will buy. A nominal 4×8 is 48 by 96 inches. A metric sheet is often 1219 by 2438 mm, a little under that. Measure if the last part is close.
- Set trim to whatever you cut off each edge before laying parts out. Use zero if the factory edge stays.
- Set the kerf to the tooth path. A full-kerf table-saw blade is about ⅛ inch (3.2 mm). A thin-kerf blade is closer to 3/32 inch (2.4 mm).
- Add each rectangular part. Turn rotation off when the grain has to run a chosen way.
- Read the sheet count, the unused share, and the drawing. Anything listed as unpacked does not fit that sheet in either orientation.
The formula
Each part sits on a shelf. The next part on that shelf must be no taller than the shelf, and the cursor steps forward by the part plus the kerf.
- Shelf. A horizontal band as tall as the first part placed in it. Later parts on the band have to fit that height.
- Kerf. Added between parts and between shelves. It is not added after the last part on a shelf beyond the gap the cursor already left.
- Rotation. When it is allowed, the packer tries the short way and the narrow way and keeps the better buy.
Worked example
Four 24 by 48 inch rectangles on a 48 by 96 inch sheet, with rotation allowed, no trim, and no kerf, land on 1 sheet. The parts use the whole sheet.
The same four parts with a ⅛ inch kerf need 2 sheets. The drawing is a shelf layout, not a prize-winning nest. If the grain has to run one way, lock rotation and expect to buy more.
What it will not decide
- Rectangles only. No curves, no mitred edges, no bookmatching, no grain figure.
- The layout is a heuristic. Odd mixes of sizes often pack tighter by hand.
- It does not reserve a panel-saw fresh cut beyond the kerf and trim you type.
Questions
Why did four parts that “should” fit need a second sheet?
Kerf and trim are real wood. Four 24 by 48 parts fill a 48 by 96 sheet exactly when the blade removes nothing. An ⅛ inch kerf pushes the fourth part onto another sheet. The worked example is that case.
Can I stop it turning a part?
Yes. Lock the grain on that row. The part stays in the width and height you typed, and if that orientation does not fit the sheet it is reported as unpacked.
Is the drawing to scale?
Yes, within the sheet’s own proportions. Labels are omitted when a part is too small to hold text. The counts above the drawing are the numbers to buy from.