How to nest furniture parts on a 4 × 8 ft plywood sheet
The short answer: nesting is arranging the parts of a design on your sheet so they use as little material as possible and still leave room for the bit. A standard 4 × 8 ft sheet is 48 × 96 inches (1220 × 2440 mm), and the plans on this site nest the parts for you.
What good nesting does
- Fits all the parts on as few sheets as possible, so you buy less plywood.
- Leaves a margin at the edge of the sheet, where it is often rough or out of square.
- Leaves a gap between parts, at least as wide as your bit, so a part does not touch its neighbor.
Margin and spacing
The sheet edge is the worst part of the board, so the plans leave a margin there (a little under half an inch by default). Between parts they leave a gap larger than the bit diameter. You can change both in the material settings of any model.
Rotation and grain
Parts can be turned 90 degrees to fit more of them on a sheet. If the grain direction matters for appearance or strength, turn rotation off: fewer parts per sheet, but all the grain runs the same way.
Reading the sheet layouts
Every download has a PDF assembly guide with a page for each sheet. Each part has a reference such as A1 or B2: the letter is the part in the parts list and the number is the copy. The guide also shows how much of each sheet is used. Mark each part with its reference in pencil as it comes off the machine, so assembly is quick.
Smaller machines
If your CNC bed is smaller than 4 × 8 ft, set your own sheet size in the material settings and the parts are nested to fit. Each part still has to fit on the sheet by itself, and the preview tells you when one does not.
Why layout also saves money
A tighter layout can save a whole sheet of plywood and shorten the cutting time. Shops commonly bill machine time by the hour, with small shops around $35 to $60 per hour, so a job that cuts faster costs less. See how much a CNC furniture project costs for a worked example at $45 per hour.
Frequently asked questions
Is a 4 × 8 ft sheet really 48 × 96 inches?
Yes, in nominal terms: 1220 × 2440 mm. Check your own sheets, as actual sizes vary slightly.
Can I use a smaller CNC bed?
Yes. Set your own sheet size in the material settings and the parts are nested to fit it. Each part still has to fit on the sheet.
What gap should I leave between parts?
At least the diameter of your bit. The default is a little more than that.