Definition of countersink in English:

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Pronunciation: /ˈkoun(t)ərˌsiNGk/

verb (past and past participle countersunk /-ˌsəNGk/)

[with object]
1Enlarge and bevel the rim of (a drilled hole) so that a screw, nail, or bolt can be inserted flush with the surface.
Example sentences
  • Drill and countersink screw holes for mounting screws.
  • Drill four 3/16-inch clearance holes in each rib before countersinking the top surface to bring the screw head flush.
  • I've also countersunk the holes so no screwheads stick up later on.
1.1Drive (a screw, nail, or bolt) into a countersunk hole.
Example sentences
  • It's helpful to first pre-drill a small hole in the wood where you want to countersink the brass screws.
  • Flat heads are always countersunk or rest flush with the surface.
  • A thin layer of thinset adhesive is applied to the top of the plywood using a notched trowel, then the cement board is put in place and secured with flathead screws that are countersunk into the surface.
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