[verb, noun koun-ter-singk; verb koun-ter-singk]
verb (used with object), coun·ter·sank, coun·ter·sunk, coun·ter·sink·ing.
to enlarge the upper part of (a cavity), especially by chamfering, to receive the cone-shaped head of a screw, bolt, etc.
to cause (the head of a screw, bolt, etc.) to sink into a prepared depression so as to be flush with or below the surface.
a tool for countersinking a hole.
a countersunk hole.
Origin of countersink
First recorded in 1810–20; counter-
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for countersunk
Historical Examples of countersunk
Two holes are bored and countersunk for screws to hold the post and handle.
Holes are bored and countersunk at the places shown in the drawing.
Holes are bored in the front piece of the cart and countersunk on the inner side.
Two holes are bored and countersunk for the screws which hold it to the mill base.
Holes for the screws at the ends were bored and countersunk.
British Dictionary definitions for countersunk
verb -sinks, -sinking, -sank or -sunk (tr)
to enlarge the upper part of (a hole) in timber, metal, etc, so that the head of a bolt or screw can be sunk below the surface
to drive (a screw) or sink (a bolt) into such an enlarged hole
Also called: countersink bit a tool for countersinking
a countersunk depression or hole
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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