Parts of a Drill bit
- Land / Margin
- Body Clearance
The cone shaped end which does the cutting is called the point. It consists of a dead centre, lips or cutting edges, and a heel.
This is the driving end of the drill which is fitted on to the machine. Shanks are of two types.
Taper shank, used for larger diameter drills, and straight shank, used for smaller diameter drills.
This is a part of the taper shank drill which fits into the slot of the drilling machine spindle.
The portion between the point and the shank is called the body of a drill.
The parts of the body are flute, land/margin, body clearance and web.
Flutes are the spiral grooves which run to the length of the
drill. The flutes help
- To form the cutting edges
- To curl the chips and allow these to come out
- The coolant to flow to the cutting edge.
6. Land / Margin
The land/margin is the narrow strip which extends to the entire length of the flutes.
The diameter of the drill is measured across the land/ margin.
7. Body Clearance
Body clearance is the part of the body which is reduced in diameter to cut down the friction between the drill and the hole being drilled.
Web is the metal column which separates the flutes. It gradually increases in thickness towards the shank.