A drill cuts by using a rapidly spinning, multi-point bit that is pressed firmly against the material, forcing its sharp edges to shave off material.
The Cutting Mechanism
At its core, drilling is a material removal process driven by rotational force and downward pressure. The drill bit, which is typically a rotary cutting tool with multiple cutting edges, is the primary tool used for this task. The process involves two key actions:
- Pressure: The drill bit is pressed against the work-piece, the material you intend to drill through.
- Rotation: The bit is simultaneously rotated at rates from hundreds to thousands of revolutions per minute (RPM), depending on the material and drill type.
This combination of pressure and high-speed rotation forces the cutting edge (or edges) of the drill bit to engage with the work-piece.
How Material is Removed
When the rotating cutting edge is pressed against the material, it doesn't simply grind it away. Instead, the sharp edges are designed to slice, shear, or scrape away small pieces of the material.
This action effectively cutting off chips (swarf) from the hole as it is drilled. These chips are the waste material produced during the drilling process. The helical flutes on most drill bits help to lift these chips out of the hole, preventing clogging and allowing the cutting edges to continue working.
Here's a simple breakdown of the action and outcome:
| Action | Outcome |
|---|---|
| Drill bit pressed & rotated | Cutting edge forced against work-piece |
| Cutting edge engages material | Material is cut off |
| Material removed | Chips (swarf) are formed and expelled |
Understanding this fundamental mechanism of pressure, rotation, and cutting edge action is key to knowing how a drill performs its essential function of creating holes.
