How to countersink a screw

Last updated: July 12, 2026

Countersinking cuts a small cone-shaped recess so a flat-head screw sits flush with the surface — or just below it — instead of standing proud. It's what gives screwed joints a clean, snag-free finish. Here's how to do it, and how it differs from a counterbore.

What countersinking is — and why bother

A countersink is a cone-shaped recess cut into the top of a hole, matching the tapered underside of a flat-head screw. Cut it to the right depth and the head drops flush with the surface, or a hair below, instead of sitting proud. You countersink for three reasons: it looks clean and finished, it keeps the head from snagging hands, cloth or moving parts, and it lets you hide the head under wood filler or a wooden plug for an invisible fastening.

Countersink vs. counterbore

These two get mixed up constantly, so it's worth being precise:

• Countersink — an angled, cone-shaped recess that matches a flat-head screw's tapered head, so the head sits flush. The angle matters: 82° is the common wood-screw standard in the US, while many metric screws use 90°.
• Counterbore — a straight-walled, flat-bottomed hole drilled deeper into the surface. You counterbore to recess a hex-bolt head or a washer, or to sink a screw head well below the surface so it can be capped with a wood plug or dowel.

Rule of thumb: countersink so a flat-head screw sits flush; counterbore when you want the head buried deeper for a plug, or to seat a washer or bolt head. Some combination bits do both — a countersink cone plus a deeper plug bore above the pilot.

How to countersink a screw, step by step

1. Mark the spot where the screw goes.
2. Drill the pilot hole first, sized to the screw — this is also what keeps the wood from splitting.
3. Cut the countersink with a countersink bit, holding the drill square to the surface. Go slowly and check often; you want the recess just deep enough for the head to sit flush or a touch below.
4. Test on scrap of the same material first — drive a screw and eyeball the head, then adjust the depth before you touch the real workpiece.
5. Drive the screw until the head seats in the recess, and stop. Don't over-drive it deeper.

The one-pass combination bit

If you're countersinking more than a couple of holes, a combination countersink-pilot bit is worth it. It's a tapered drill bit with an adjustable countersink collar (some also carry a plug cutter) that drills the pilot and cuts the countersink in a single plunge, at a consistent depth every time. For repeated work — a row of shelf screws, a whole cabinet — it's a real time-saver and keeps every head sitting the same.

Common mistakes

• Too deep — the head sinks too far, weakening its grip on the surface and, in thin stock, sometimes blowing straight through. Sneak up on the depth.
• Too shallow — the head stands proud and snags; the recess needs to fully swallow the head's taper.
• Wrong-angle bit — a countersink that doesn't match the screw head's angle leaves a gap or only touches at one point. Match the bit to your screws (82° for most US wood screws).
• Skipping the pilot — countersinking without a pilot hole still risks splitting. The countersink shapes the recess for the head; the pilot handles the threads. You want both.

The bottom line

Countersinking is simple: pilot hole first, then a matched countersink bit to the right depth, tested on scrap. For anything more than a few holes, a combination bit makes it faster and more consistent — and because a countersink always pairs with a pilot hole, start by getting the pilot size right.