How do I stop plywood splintering when I cut it?

Plywood's surface is a thin cross-grained veneer with nothing supporting it, so it lifts and tears as the teeth pass through. Every technique here does the same thing in a different way: support that veneer.

What you'll need

• fine blade, 40 tooth or higher
• masking tape
• sharp knife (optional)
• sacrificial backing sheet
• clamps and a straightedge

Step by step

1. Work out which face the teeth exit.A circular saw's teeth travel up through the material, so the top face tears. A standard jigsaw blade also cuts on the up stroke and tears the top. A table saw's teeth exit downwards, so there it is the underside.
2. Put the good face away from the exit.With a hand-held circular saw or a jigsaw, that means good face down. It is free and it makes the biggest single difference.
3. Fit a fine blade.Forty teeth or more on a circular saw, a fine or downcut blade on a jigsaw. Each tooth takes a smaller bite so it shears rather than levers.
4. Run masking tape along the cut line on both faces.The tape holds the surface fibres together as the teeth pass. Low-tack tape avoids lifting the veneer when you remove it — peel it back on itself, slowly.
5. Score the line with a sharp knife.A firm cut through the face veneer along the line severs the fibres before the saw reaches them, so any tearing stops at the score.
6. Back the sheet with a sacrificial board.A sheet of cheap MDF or ply underneath, cut through into, supports the underside fibres completely.
7. Clamp a straightedge and let the saw run against it.A wandering cut tears far more than a guided one, because the blade is being twisted in the kerf.
8. Set the blade depth just past the material.About 5mm proud of the underside. A blade set very deep meets the veneer at a steeper angle and lifts it more.
9. Feed at a steady moderate rate.Forcing the saw makes it tear; going too slowly burns and rubs. Consistent pressure with the saw doing the work is the target.
10. Clean up with a block plane or a sanding block if needed.A light chamfer along the arris removes any remaining fuzz and makes the edge feel finished.

Tips

• Score the line with a knife and put tape over it. Together they solve most of the problem before the saw is even switched on.
• A downcut jigsaw blade reverses which face tears — useful when the good face has to be uppermost.
• Birch ply and hardwood-faced ply splinter much less than softwood ply. Sometimes the material is the answer.

Common mistakes

• Cutting with the good face up under a circular saw — The teeth exit through the top face, so that is exactly the face that lifts and tears. Turning the sheet over costs nothing and fixes it.
• Ripping masking tape off quickly — It takes the loosened veneer with it, undoing the whole point of using it. Peel slowly, back on itself, at a shallow angle.

If it doesn't work

Questions people ask