What's the difference between countersink and counterbore?

A countersink is an angled, cone-shaped recess that lets a flat-head screw sit flush with the surface. A counterbore is a straight-walled, flat-bottomed, deeper hole, used to recess a bolt head or washer, or to sink a screw head below the surface so it can be hidden under a wood plug. Countersink for flush; counterbore for buried-and-plugged.

How deep should you countersink a screw?

Just deep enough that the head sits flush with the surface, or a hair below. Too deep weakens the head's grip and can blow through thin stock; too shallow leaves the head proud and snagging. Test the depth on a scrap of the same material first.

Do you drill a pilot hole before countersinking?

Yes. Drill the pilot hole first, or use a combination bit that does both in one pass. The pilot guides the threads and keeps the wood from splitting; the countersink only shapes the recess for the head. They do two different jobs.

How to Countersink a Screw (and Countersink vs. Counterbore)

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

Mark the spot where the screw goes.
Drill the pilot hole first, sized to the screw. This is also what keeps the wood from splitting.
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.
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.
Drive the screw until the head seats in the recess, and stop. Don't over-drive it deeper.

Need the pilot size first?

Find your pilot-hole size

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.

How to countersink a screw