Classification of Drills

Drills are manufactured in several different forms and sizes. The commonly used drills can be classified in many ways, as follows :

• According to the Type of Shank They Carry

(a) Parallel shank

(b) Taper shank

• According to the Type of Flutes

(a) Flat or spade drills (parallel longitudinal flutes)

(b) Twist drills (spiral/helical flutes)

• According to Length

(a) Short series drills

(b) Stub series drills

(c) Long series drills

• According to Applications

(a) Core drills

(b) Drills for long hole drilling

(c) Centre drills

(d) Masonary drills

• According to the Tool Material

(a) High speed steel drills

(b) Carbide Tipped Drills