Twist Drill Nomenclature
Drill nomenclature comprises the various parts and important geometric parameters of cutting point. They are shown in Figure 11 and defined below:
The shank is the part of drill which is held in machine spindle and driven by it.
Flattened end of shank, intended to fit into a slot in the drill holder. Reduced p
Reduced p
Fig 11 : Twist Drill Nomenclature
Then, there is large number of special drills manufactured against order to meet specific requirements. Such drills can be classed as special drills.
The fluted portion of a drill.
Flutes are helical grooves formed in the body of drill.
The central portion of the body which separates the flutes and runs through entire length of drill.
The edge formed by intersection of flank and face, and correspond to the cutting edge of a single point tool.
It is the cylindrical ground surface on the leading edges of drill flutes.
The diameter over the surface of the body which is situated behind the land.
Narrow surface along the groove which keeps the drill aligned.
The edges formed by the intersection of flute surface and body clearance.