Sheet goods look easy but splinter and blow out without the right tool. The best drill bits for plywood and MDF cut the surface fibres cleanly before removing waste, so both faces stay crisp and free of the ragged tear-out that ruins visible panels.
What to Look For
Plywood is layered veneer with alternating grain, and MDF is compressed fibre that is abrasive and dulls edges quickly. The two enemies are tear-out on the top face and blow-out on the bottom face, both of which show badly on finished cabinet parts. You want a bit whose outer spurs sever the fibres at the rim first, plus a geometry that leaves a flat, clean-walled hole rather than a torn, tapered one. Because MDF wears cutting edges fast, edge durability matters as much as sharpness — a bit that goes dull halfway through a sheet starts to crush and fuzz the fibre instead of slicing it, and the resin binder in MDF only accelerates that wear. Thinner plywood is especially prone to splintering because there is little material behind the veneer to support it.
The Best Type of Bit for Plywood and MDF
Brad-point wood bits are ideal for clean, accurate holes because the sharp centre point locates precisely and the side spurs slice the veneer before the flutes lift waste. For flat-bottomed holes and larger diameters, a spade or auger-style bit works well. Whatever you choose, favour well-made steel that holds an edge in abrasive fibreboard.
- Brad point: the centre spur prevents wandering on slick, sanded plywood faces.
- Side spurs: score the veneer rim to stop splintering on the top layer.
- Backer board: essential for plywood — scrap behind the sheet stops exit blow-out.
- Sharp edges: MDF abrades bits fast, so keep bits sharp for clean, low-dust cuts.
Preventing Blow-Out
Ease off feed pressure as the tip nears the far face, or drill from both sides so the holes meet in the middle for a perfect edge on show surfaces. Clamp the panel firmly and run moderate speed rather than flat out, which only builds heat in MDF and can singe the walls of the hole. American-made bits hold their spurs sharp longer, which matters most in abrasive fibreboard where imported edges wear down within a single project and start tearing.
Pilot Holes for Fasteners
Plywood edges split when screwed and MDF crumbles or mushrooms around a driven screw, so pilot holes are non-negotiable in both materials. Driving into the edge of MDF without a pilot is the fastest way to blow the panel apart, since the loose fibre offers almost no resistance to a wedging screw. Match the pilot diameter to the fastener, and add a shallow countersink so heads sit flush rather than dimpling the surface. Use our sizing references to pair each screw with the right bit so fasteners seat firmly without splitting the panel or stripping the fibre.