Countersink

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countersink

[′kau̇nt·ər‚siŋk]
(design engineering)
The tapered and relieved cutting portion in a twist drill, situated between the pilot drill and the body.

Countersink

 

(Russian, zenkovka; from German senken, “to sink, lower”), a cutting tool used for countersinking. Countersinks usually form part of a set with centering drills. The sizes of countersinks in each set depend on the diameter of the hole; in all sets, the vertex angle is 60°. Coun tersinks are made for chamfering center holes with diameters of 0.5 to 1.5 mm (ordinary countersinks), for holes with diameters of 0.5 to 6 mm (with or without protective taper), and for holes with diameters of 8 to 12 mm (with tapered stem). Countersink cutting elements are made from high-speed steel; countersinks with tapered stems are welded and the stems are made from carbon structural steel.

countersink

countersink
A boring bit having a conical-shaped cutter; used to make a depression to receive the head of a screw or bolt so that it does not protrude above the surface.
References in periodicals archive ?
They all drove easily with no stripping or breakage and sat perfectly flush without the need for a countersink bit.
Fasten with four screws per side, predrilling all the holes with a countersink bit to avoid splitting the wood.
You can drill countersink and pilot holes in one stroke with a countersink bit ($4).
Tools Smoothing plane Portable circular saw Tape measure and straight edge Combination square and pencil Coping saw (or electric jigsaw) Hammer Spoke shaves: round-bottom and flat-bottom Electric drill Drill bits: 2mm, 3mm, 5mm, countersink bits Utility knife and scissors Cork sanding block or electric sander Screwdriver (cross-headed or slotted) Here's how: Preparing the boards 1.
Countersink bits for the drill are always recommended so the fiberglass doesn't fracture.
Countersink bits widen holes so flathead screws may be flush mounted below the surface for a finished appearance.
Tools required: Sandbug electric sander; Gofer X ultra compact rechargeable screwdriver; Pincers; Pencil; Power drill with twist and countersink bits and a knife