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.
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.
CBN is a much harder abrasive than either silicon carbide or corundum and creates a sharper and more durable cutting edge with precise tolerances.
Radially-adjusted relief grinding ensures that the cutting edge is always the highest point, and combined with axial relief grinding, guarantees a smooth, low-heat, chatter-free cut up to 30% faster than competing countersink bits.
These tough bits are suitable for all standard industrial materials: steel, cast iron, stainless steel, non-ferrous metal, thermoplastics, and duroplastics.
Best results are achieved at low cutting speeds. Use of cutting oil or paste will provide longer tool life and superior quality work.