Split point is self centering reducing the need for end thrust.
The 135° point provides superior performance when drilling harder steel materials.
In most situations it will produce thicker chips minimising work hardening of the cavity.
Faster penetration reduces abrasion and friction along the cutting edges.
Black Finish 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.