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
Verb
insert (a nail or screw below the surface, as into a countersink)
例句
A tool for making a countersink. 做螺丝钉孔的工具
To drive(a screw or bolt) into a countersink. 将钻或螺栓置入埋头孔
Orthopaedic instruments.Drills, taps and countersink cutters for use with osteosynthese screws with asymmetrical thread and spherical under-surfaces. 外科医疗器械.;矫形外科器械
