How Does a Hammer Drill Work?

Hammer drills are also known as rotary hammer drills, roto hammers and impact drills.  These tools are used to drill into extremely hard surfaces.  Masonry materials including rocks, concrete and bricks require the use of this specialized tool.  The unique movement hammer drills employ is what allows them to penetrate into hard surfaces.

There is a difference between hammer drills and regular drills.

Regular drills simply rotate the drill bit in a set position.  This is due to the stationary characteristic of the chuck.  Hammer drills have a moveable chuck that allows for the drill bit to move forward and backward as it rotates.

What is a chuck?

The chuck is the portion of a drill that holds the drill bit.  Opening the chuck is similar to opening a jar; it rotates left and right to loosen and tighten.  Some chucks require a key for this process, while others are keyless.

Why is the moveable chuck important?

The moveable chuck adds a forward and backward motion to the rotating drill bit.  This motion creates a hammering effect which knocks additional chunks from the drilled material. As a result, the drill bit can easily penetrate deeper into the material.

The speed with which the chuck hammers is important with regard to how effectively the hammer drill operates.  Impacts per minute, or IPM, is the measurement that reflects the number of times the chuck hammers each minute.  The higher the IPM, the more effective the hammer drill.