Countersink vs. Spotface

Countersinknoun

a cylindrical recess, typically machined around a hole to admit a screw so that it sits flush with a surface.

Countersinkverb

(transitive) To create such a conical recess.

Countersinkverb

(transitive) To cause to sink even with or below the surface.

Countersinkverb

To chamfer or form a depression around the top of (a hole in wood, metal, etc.) for the reception of the head of a screw or bolt below the surface, either wholly or in part; as, to countersink a hole for a screw.

Countersinkverb

To cause to sink even with or below the surface; as, to countersink a screw or bolt into woodwork.

Countersinknoun

An enlargement of the upper part of a hole, forming a cavity or depression for receiving the head of a screw or bolt.

Countersinknoun

A drill or cutting tool for countersinking holes.

Countersinknoun

a hole (usually in wood) with the top part enlarged so that a screw or bolt will fit into it and lie below the surface

Countersinknoun

a bit for enlarging the upper part of a hole

Countersinkverb

insert (a nail or screw below the surface, as into a countersink)

Countersink

A countersink (symbol: ⌵) is a conical hole cut into a manufactured object, or the cutter used to cut such a hole. A common use is to allow the head of a countersunk bolt, screw or rivet, when placed in the hole, to sit flush with or below the surface of the surrounding material (by comparison, a counterbore makes a flat-bottomed hole that might be used with a socket-head capscrew).

Spotfacenoun

a shallow circular or cylindrical recess, machined on (for example) a cast part to offer a flat face against which to seat a fastener; a shallow counterbore

Spotfaceverb

(transitive) to create or fashion a spotface

Spotface

A spotface or spot face is a machined feature in which a certain region of the workpiece (a spot) is faced, providing a smooth, flat, accurately located surface. This is especially relevant on workpieces cast or forged, where the spotface's smooth, flat, accurately located surface stands in distinction to the surrounding surface whose roughness, flatness, and location are subject to wider tolerances and thus not assured with a machining level of precision.