Drill Bit Nomenclature

Parts of a Drill bit

  1. Point
  2. Shank
  3. Tang
  4. Body
  5. Flutes
  6. Land / Margin
  7. Body Clearance
  8. Web
Drill Bit Nomenclature
Drill Bit Nomenclature

1. Point

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.

2. Shank

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.

3. Tang

This is a part of the taper shank drill which fits into the slot of the drilling machine spindle.

4. Body

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.

5. Flutes

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.

Drill Bit Nomenclature
Drill Bit Nomenclature

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.

8. Web

Web is the metal column which separates the flutes. It gradually increases in thickness towards the shank.

Drill Bit Nomenclature
Drill Bit Nomenclature
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