Best plywood for CNC furniture: what to buy and what to avoid
The short answer: for furniture whose edges show, buy void-free birch or hardwood plywood with a sanded face, in 3/4" (about 23/32", 18 mm) sheets that lie flat on the rack. Use cheaper sanded pine plywood for painted pieces, and keep construction sheathing for jigs and test cuts.
What matters when you choose plywood for a CNC
- Flatness: a warped sheet will not sit on the table, and the depth of your cut changes across the part. Stand it on its edge in the store and sight along it.
- Voids in the core: a gap inside the board shows on the cut edge and can make a tenon break. Void-free cores cost more but cut clean.
- Consistent thickness: joints are cut for one thickness, so sheets that vary by a few hundredths of an inch cause loose or tight fits. Read why 3/4" isn't 3/4".
- Face veneer: a very thin face veneer sands through easily. If you plan to sand and finish by hand, ask for a sanded face with a visible, even veneer.
- Glue and emissions: for indoor furniture, and especially for children's rooms, look for panels marked as low-emission (for example, compliant with the TSCA Title VI / CARB formaldehyde rules).
The common choices
- Baltic birch: many thin plies, a void-free core and a neat striped edge that looks good left bare. It is usually sold in 5 × 5 ft sheets, so check that your nesting fits before you buy. A great pick when you can find it.
- Hardwood plywood (birch, maple, oak or walnut faces): the usual choice for furniture in a 4 × 8 ft sheet. The core varies by supplier, so ask whether it is a veneer core and whether it has voids.
- Sanded pine or spruce plywood: softer and cheaper, with more voids and a more visible grain. Good for painted furniture, shelves and kids' pieces you will finish with an opaque coat.
- Construction sheathing (CDX): rough faces and many voids. Fine for jigs, fixtures and trial cuts, not for furniture.
How to check a sheet before you buy
- Look at the edges for gaps and for plies that are very uneven in thickness.
- Stand the sheet on one edge and check that it is flat, with no twist or bow.
- Measure the thickness with calipers in a few spots, away from the edges.
- Buy all the sheets for one project from the same batch if you can, and check the receipt for the grade.
Sheet size and the layout
Most plans are laid out for a 4 × 8 ft sheet. If you buy 5 × 5 ft sheets, set the sheet size before you download so the parts are nested for it. The guide on nesting furniture parts on a 4 × 8 sheet shows how the layout affects how many sheets a project uses.
Frequently asked questions
Is Baltic birch the best plywood for CNC furniture?
It is one of the best, thanks to its void-free core and clean edge. It is usually sold in 5 x 5 ft sheets, so check that your layout fits. Good hardwood plywood in 4 x 8 ft sheets also works well.
Can I use construction plywood for furniture?
Not for furniture you will show. Construction sheathing has rough faces and voids in the core. It is fine for jigs, fixtures and test cuts.
How thick should the plywood be?
Most plans here are made for 3/4" plywood, which usually measures about 23/32" (18 mm). Always measure your own sheets and enter the real thickness.