HSS Straight Shank Twist Drill Bit: A Complete Overview

1.  Heavy-duty construction for drilling in tough, high-tensile and work-hardening materials under extreme operation conditions.
2.  Manufactured from premium 5% or 8% cobalt high speed steel increasing hot hardness and extending drill wear life.
3.  135°split-point is self-centering for reduced thrust and easier penetration
4.  Ideal for drilling hard material such as stainless steel.

Drill points between normal 118°and 135° split point:

1.  118°point angles are used primarily in softer material such as mild steels and cast irons.

2.  135°split point should be used to cut harder steel materials and especially in deep holes over 4 times the drill diameter. With a 135°split point, cutting harder materials will produce thicker chips, minimizing work hardening of the cavity short.
The length of the lips on a 135°split point, measured from the axis to the cuter corners, is relativity short. This enables quicker penetration into the workpiece and reduces thrust and abrasion along the cutting edges.

3.  When repointing a standard 118°point to 135°，make a lip correction to reduce the hook of the cutting face.