- to enlarge the top part of (a hole in metal, wood, etc.) so that the head of a bolt, screw, etc. will fit flush with or below the surface
- to sink the head of (a bolt, screw, etc.) into such a hole
- a bit for countersinking holes
- a countersunk hole
Used by arrangement with John Wiley & Sons, Inc.
- A hole with the top part enlarged so that the head of a screw or bolt will lie flush with or below the surface.
- A tool for making such a hole.
- To make a countersink on or in.
- To drive (a screw or bolt) into a countersink.
single-flute countersink bit