How to Drill Near the Edge of Plywood Without Splitting It

No single bit size works for every plywood pilot hole near an edge. For a regular wood screw going into the broad face of the panel, start with a bit about as wide as the screw's core. Then test that bit and screw in matching scrap before you drill the finished piece.

If the screw drives smoothly and holds in the scrap without cracking, use the same setup on the project. If it resists or a crack starts, change the bit size on scrap first, not on your finished panel.

What Pilot Bit Should You Use Near a Plywood Edge?

Use a bit close to the screw's core diameter rather than the full width of the threads. The core is the solid center shaft of the screw, measured with the threads left out.

To check this by eye, hold the bit up against the screw. You should still see the threads sticking out on both sides, but not the center shaft.

The reason has to do with the threads. A general guide to wood-screw pilot holes says a pilot near an edge lets the threads cut cleanly into the walls of the hole. Without one, the wood has to compress to make room for the whole screw. That outward pressure is what splits material close to an edge. The same guide puts the pilot at roughly the shank diameter minus the threads. Keep in mind that this is general wood-screw advice, not a plywood specification.

The best size can also change with the material. In its pocket-screw method, WOOD Magazine uses a 7/64-inch pilot for a #8 screw in hardwood and a 3/32-inch pilot in softwood. Those numbers are for solid hardwood and softwood, so don't treat them as plywood sizes. What they do show is that one screw size doesn't fix one pilot size.

To confirm your choice, do a quick matched scrap test. This is a practical check, not a published chart. Your scrap should match the project on:

• Screw: the same screw type, gauge and length you'll use.
• Plywood: the same thickness and construction, ideally an offcut from the same sheet.
• Placement: the same distance from the edge.

Read the result before you move on. If the screw is hard to drive, test a slightly larger bit in fresh scrap. If the threads spin without biting, try a slightly smaller bit. When the screw drives without forcing, holds firmly, and leaves the edge uncracked, you've found your bit.

How to Support and Drill the Panel

Clamp the panel so it can't move, drill on your mark with the bit that passed the scrap test, and stop at the first sign of binding or cracking. This sequence applies to a screw entering the broad face near an edge.

A screw driven into the narrow edge of the plywood is a different job, so don't assume these steps carry over.

Secure the Panel and Confirm the Scrap Test

1. Confirm the project matches your test: same screw, bit, plywood and edge distance. If anything changed, run another scrap test.
2. Lay the panel flat on a solid surface and clamp it close to where you'll drill so it can't shift. This is good setup practice, but it won't stop splitting by itself.
3. Mark the hole on the face at the same distance from the edge that you tested.

Drill Without Forcing the Bit or Screw

1. Drill straight down on the mark with steady pressure. The pilot gives the threads room to cut, which lowers the risk of splitting but doesn't remove it.
2. If the bit binds, stop. Back it out and clear the hole instead of pushing harder.
3. Drive the screw slowly. If a crack starts to open, stop right away. Don't keep driving through a growing crack. Reconsider where the hole goes or how you're fastening the joint.
4. If you need a bigger pilot, test the new bit in scrap first. Don't widen a damaged hole in the project panel.

There's one separate case. If the pilot will come out the opposite face, clamp a piece of scrap behind the panel. WOOD Magazine explains that a clamped scrap backer supports the wood fibers where the bit exits and reduces tear-out. That protects the back face. It doesn't stop a screw from splitting the edge.

Once the pilot is clean, you can drive the screw with a low-speed driver. Our guide to using an electric screwdriver covers speed and control for woodworking fasteners.

FAQs

Is it a mistake to make the pilot hole too small?

It can be. A pilot that's too tight makes the screw push more wood aside, and near an edge that pressure can cause a split. The general pilot-hole guide notes that woodworkers often drill pilots too small because they think a tighter fit holds better. That guide also says a slightly larger or smaller pilot makes little difference to joint strength.

Do softwood and hardwood need different pilot sizes?

Generally, yes. The general guide says softwood often needs a pilot a little smaller than the shank, and hardwood a little larger, because hardwood compresses less under the screw. Plywood isn't covered by either of those categories, so let your scrap test decide.

What if my bit lifts fibers where it enters the face?

WOOD Magazine suggests putting masking tape on the face before you mark the layout and drill. That treats splintering where the bit goes in, not cracks along the edge.

Can I skip the pilot hole in soft material?

The general guide says a pilot hole may not be needed in softwoods such as spruce or pine. It also says it's still worth drilling one near an edge or when the placement has to be precise. A near-edge screw in plywood fits that case, so drilling the pilot is the safer choice.