Countersink bits are used to enlarge and bevel the rim of a drilled hole so a screw or bolt can be inserted flush with the surface. RUKO countersink bits make quick and clean cuts in materials such as steel, iron, non-ferrous metals and thermoplastics; bits are available in fractional sizes with 82-degree taper, or metric sizes with 90-degree taper.
RUKO 82-degree Countersink
Bits and Set
RUKO 90-degree Countersink Set
Now available in both 82° taper for UNC and UNF fasteners and DIN 335 Type C 90° taper for metric fasteners.
RUKO countersinks are CBN (cubic crystalline boron nitride) ground from fully hardened, High-Speed Steel (HSS) blanks.