countersink

Plural: countersinks

Noun

• 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
• a bit for enlarging the upper part of a hole
• A conical recess, typically machined at the mouth of a hole to admit a screw (with a matching taper) so that the screw sits flush with a surface.
• The cutter used to cut such a recess. (Also used, at less depth, for edge-breaking/deburring.)

Verb

• insert (a nail or screw below the surface, as into a countersink)
• To create such a conical recess.
• To cause to sink even with or below the surface.

Synonyms

counterbore, countersink bit, set, countersinker

Related Words

diesinking, sink, spotface