Twist Drill Nomenclature

Published: 23 Nov 2025

A twist drill is one of the most common tools used to make holes in metal, wood, and plastic. It looks simple, but every part of this tool has an important job. When you understand these parts, you can drill better and get cleaner, smoother results. So, let’s explore twist drill nomenclature in an easy and friendly way.

Twist Drill Nomenclature

Twist drill nomenclature means the names of all the parts that make up a twist drill. Each part works together to help the tool cut, rotate, and remove material smoothly.

1. Axis

The axis is the imaginary line that runs through the center of the drill. It shows the direction in which the drill spins while cutting. This line helps the drill stay straight during drilling.

2. Body

The body is the main section of the twist drill. It lies between the shank and the tip of the tool. Most cutting actions and features are found on the body.

3. Shank

The shank is the part that goes into the drill machine’s chuck. It is usually straight in small drills and tapered in larger drills. Proper shank grip ensures smooth and safe drilling.

4. Tang

The tang is the flat end of a tapered shank. It fits into the slot of the drilling machine and helps the drill rotate without slipping. It also gives better control during heavy drilling tasks.

5. Neck

The neck is the narrow part between the shank and the body. It reduces the overall weight of the tool and gives space for sharpening. It also prevents rubbing during deeper drilling.

6. Margin

The margin is a thin, raised line that runs along the body of the drill. It does not cut but keeps the drill steady while rotating. It also reduces friction between the drill and the material.

7. Flutes

Flutes are spiral grooves carved along the body of the drill. They help form the cutting edge and guide chips out of the hole. Proper flute design improves chip removal and keeps drilling smooth.

8. Lips

The lips are the two main cutting edges at the tip of the drill. They remove material as the drill spins at high speed. Sharp lips help create clean, accurate holes.

9. Dead Center (Chisel Edge)

The dead center is the point where both cutting lips meet. It is at the very tip of the drill and helps you start the hole. A well-shaped dead center keeps the drill from wandering.

10. Flank

The flank is the surface behind the cutting lips. It provides relief so the drill can cut without rubbing the material. This helps the drill work cooler and last longer.

Conclusion

A twist drill has many simple but important parts, and each one helps the tool work smoothly. When you understand the twist drill nomenclature, you can choose the right drill and use it with more confidence. This knowledge also helps you get cleaner holes and better results in every project.