Working With Plywood: Clean Cuts, Circles, Joints and Edges

Full sheets are commonly cut down to rough size on supports before parts are cut to final size. How to support it, set depth and guide a circular saw is in cutting plywood with a circular saw; a plunge saw on its rail in track saws; a shop-made track and a sheet platform in DIY track saw. What is particular to plywood is the face: its thin veneer splinters wherever the teeth leave the wood.

• Know which way the teeth cut. A circular saw's teeth cut upward, so DEWALT says to put the good face down; splintering stays on the face that is up.
• Use a fine-tooth blade. DEWALT's track-saw manual names a fine-tooth blade for plywood; blades are compared in circular saw blades.
• Hold the fibres down at the line. A track's trimmed splinter strip does this; on a plain saw, a guide clamped tight to the face helps.
• Score first on veneered faces. A shallow first pass on the line, then the full cut — the scoring stops on plunge saws are covered in track saw safety.

For a round tabletop or an opening, a router swung on a fixed pivot — a circle guide or a trammel — cuts a true circle: Bosch's deluxe edge guide pivots for circles and arcs, as described in router jigs, with depth per pass as your router and bit makers set it. A jigsaw or band saw cuts close to a drawn line and the edge is faired afterwards. With plywood, plan two things the solid-wood version does not need: the face veneer splinters where a cutter leaves it, as it does with a saw, so put the good face where the cutter enters, and the routed edge exposes every ply, including any void in a veneer core — choose a void-free core or a multi-ply panel if the edge will show.

• Measure, do not trust the label. A 23/32 Performance Category panel can measure anywhere from 0.688 to 0.750 in, and Columbia notes veneer core varies in thickness more than MDF or particleboard. Size dadoes, grooves and rabbets to the sheet in hand — the method is on the plywood thickness chart.
• Cut them to fit. A dado stack shimmed to the measured thickness, or a router taking a second pass — see dado blades and router jigs.
• Glue on long grain. The face plies of a dado's walls are long grain; the crossband plies on a cut edge are end grain. Joints that put face to face glue best; a butt joint into a plywood edge depends on fasteners — see choosing a joint.

A cut edge shows the plies. Left exposed — on multi-ply birch made for the purpose — it can be a feature. Otherwise it is covered with veneer banding or a solid-wood strip.

• Straight edges. TECE describes its pre-glued banding as essentially for straight edges.
• Heat limit. TECE says correctly applied banding keeps its integrity up to about 60–65°; keep banded edges away from hot surfaces.
• Solid-wood edging. A strip glued to the edge, grain running along it, then planed or routed flush, takes knocks better than 0.55 mm of veneer and can be shaped. Glues are compared in choosing a wood glue.

Plywood's crossed layers make it resist splitting, so the Wood Handbook calls it an excellent choice for fasteners placed very near its edges. The core matters too: Columbia rates MDF core above particleboard core for screw holding, and particleboard swells most if it gets wet. Drill pilot and clearance holes as the screw maker recommends, and where small parts would expose internal voids, the Handbook notes that plywood can be ordered with a solid core.

Purdue gives face veneer as generally 1/36 to 1/50 in thick — under a millimetre — so there is little to sand before the core shows. Use a fine grit, light pressure and a sander kept flat, and check the surface often; why the face is so thin is explained in veneer, and sanders and grits in sanding wood.

Plywood types, grades and cores are in the plywood guide; sheets are counted with the plywood calculator and laid out with the cut list optimizer.