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countersink

American  
[koun-ter-singk, koun-ter-singk] / ˈkaʊn tərˌsɪŋk, ˌkaʊn tərˈsɪŋk /

verb (used with object)

countersinks, present (3rd person singular) countersank, past countersunk, past participle countersinking present participle
  1. to enlarge the upper part of (a cavity), especially by chamfering, to receive the cone-shaped head of a screw, bolt, etc.

  2. 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.


noun

  1. a tool for countersinking a hole.

  2. a countersunk hole.

countersink British  
/ ˈkaʊntəˌsɪŋk /

verb

  1. 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

  2. to drive (a screw) or sink (a bolt) into such an enlarged hole

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

noun

  1. Also called: countersink bit.  a tool for countersinking

  2. a countersunk depression or hole

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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Present

Past

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Etymology

Origin of countersink

First recorded in 1810–20; counter- + sink

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Each takes up the question of how American infamy functioned as an unexamined countersink to the easy legend of American virtue.

From Slate Jun. 20, 2019

When drilling holes in fiberglass, first drill a tiny pilot hole, then use a countersink bit to bevel the edges before drilling a larger hole.

From Time Magazine Archive

He had taught his sons to "fell a tree, sow, cultivate and harvest, save money, countersink a nail, make cider with a hand press, clean a gun, sail a boat, etc."

From Time Magazine Archive

“Was it the countersink that made it explode?” he asked.

From "October Sky" by Homer Hickam

How about we countersink the nozzle, one side or the other or both?

From "October Sky" by Homer Hickam

In one corner of the large basement was a good-sized workbench, lighted by two windows, and equipped with several neatly-arranged shelves, which now held a divers collection of chisels, bits, countersinks, etc.

From Around the World in Ten Days by Fraser, Chelsea Curtis

CalipersToList Files for various descriptions, countersinks, frame and hack saws.

From Practical Mechanics for Boys by Zerbe, James Slough

Then there are punches, broaches, drills, calipers, countersinks, files, etc., etc.

From Scientific American Supplement, No. 664, September 22,1888 by Various

The smaller sizes of countersinks are sometimes made as in Fig.

From Modern Machine-Shop Practice, Volumes I and II by Rose, Joshua

We also like that it comes with countersunk washers and brass screws, which give this holder a streamlined look when hung.

From Slate Jan. 4, 2019

The chocks in which these boats rest are provided with gunmetal wheels, which run in transverse gunmetal tracks, countersunk on the deck.

From Scientific American Apr. 11, 2012

The water took off more than 75% of its paint surface and, the restorers found, would have stripped more had Cimabue not had the nails countersunk and covered with tiny wooden plugs.

From Time Magazine Archive

Smith simply used 2"-long, 1?4-20 flathead brass bolts with nuts and washers on the inside, countersunk every 10" to attach the ground strip to the hull bottom.

From Time Magazine Archive

Besides the countersunk nozzle, Mr. Caton showed off his new design for attaching the fins to the casement.

From "October Sky" by Homer Hickam

I told him I thought countersinking the nozzle was a good idea.

From "October Sky" by Homer Hickam

Fasten the end pieces on with screws, countersinking the heads of the vise end.

From The Boy Mechanic: Volume 1 700 Things for Boys to Do by Popular Mechanics Co.

These indentations are produced after the countersinking by the punch, shown in Fig.

From Modern Machine-Shop Practice, Volumes I and II by Rose, Joshua

A similar tool, which may, however, be used for other work besides centring and countersinking, is shown in Fig.

From Modern Machine-Shop Practice, Volumes I and II by Rose, Joshua

The object of countersinking these holes is to reduce the bearing surface of a small shaft that is to be supported in the holes and must be as free from friction as possible.

From The Boy Mechanic: Volume 1 700 Things for Boys to Do by Popular Mechanics Co.

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