Aprica Cobalt Metric Drill Set 1-6mm 

Comes in Blue Case - FREE POST

51pc  1 to 6mm  in .1mm steps (.0039”)

M35 High Speed Steel Twist Drills-  DIN338  Standard. 

Fully ground in metal case.

Manufacturing Progressively ground.

Material:  M35  5% Cobalt  High Speed Steel

Surface Finishing: Ground 7 blackened

135 dec Split point:

 Ideal for drilling harder steels, stainless axle steels.

The twist drill is the most common type of drill. The shank of the drill is held by the machine tool, which in turn imparts a rotary motion. This shank may be straight or tapered. The body of the drill is typically made up of two spiral grooves known as flutes, which are defined by a helix angle that is generally about 30 degree but can vary depending on the material properties of the workplace. The point of the drill generally forms a 135dec angle and includes a 10 degree clearance angle and chisel edge .The chisel edge is flat with web thickness of approximately 0.015 x drill diameter. This edge can cause problems in hole location owing to its ability to "walk" on a surface before engaging the workplace. In the case of brittle materials, drill point angles of less than 118 are used, while ductile materials use larger point’s angles and smaller clearance angles.