countersunkadj.n.
/ˈkaʊntəˌsʌŋk/ A. adj. Said of a hole or cavity: Cut to receive the head of a bolt, screw, etc.
Of a bolt, screw, etc.: Sunk or let in so as to lie flush with the surface.
ΘΚΠ
society > occupation and work > equipment > building and constructing equipment > fastenings > [adjective] > screw > countersunk
countersunk1795
society > occupation and work > industry > working with tools or equipment > fastening > [adjective] > with screw > of hole: enlarged to receive screw-head
countersunk1865
counterbored1920
1795 W. Felton Treat. Carriages II. (Gloss.) 216 Counter Sunk Bolt, a bolt, the head of which is let in level with the plate it fixes.
1865 E. B. Tylor Res. Early Hist. Mankind ix. 242 A piece of the same stone imbedded, with a countersunk cavity.
1884 Notes Building Constr. (ed. 2) II. 357 Countersunk rivets are those in which the point is hammered down, while hot, flush with the surface of the plate.
B. n.
(See quots.); = countersink n. 2. Hence †countersunk bit. Obsolete.
ΘΚΠ
the world > space > relative position > condition of being open or not closed > an opening or aperture > [noun] > a hole bored, pierced, or perforated > enlarging > an enlargement
countersunk1794
countersink1846
counterborea1884
1794 D. Steel Elements & Pract. Rigging & Seamanship I. 151 Countersunk, a hollow, cut by a bit round the edge of a hole. Counter-sunk bit, a bit having two cutting edges at the end, reversed to each other, which form an angle from the point.
1850 J. Greenwood Sailor's Sea-bk. 112 Countersunk, the hollows in iron plates, &c. which are excavated by an instrument called a countersunk bitt, to receive the heads of screws or nails.
This entry has not yet been fully updated (first published 1893; most recently modified version published online March 2022).
<
adj.n.1794