Description
About this item:
- 6 Piece Long Series Black Drill Set
- ANSI B94-11
- 118° chisel point with 30° helix.
- Chisel point is suitable for general purpose drilling.
- Black Finish Twist Drills (also called blue finish) achieve their distinctive colour by steam tempering, a thermal process resulting in a porous tool coating.
- This surface helps to keep lubricant on the tool, particularly important on the cutting edges, thus reducing friction and cold welding. The result is increased tool life.
- Black finish tools are generally recommended for ferrous applications where the oxide layer aids chip flow and heat dissipation.
