As the name implies, both tools hammer the concrete as the bit turns. The way the hammer force is created is the difference. The hammer drill has a clutch system with two rigid discs inside that come together and move apart to created the force. It’s more of a fast but shallow impact action that also operates at a high speed of percussion—up to 30,000 per minute in fact!
In contrast, how a rotary hammer works involve a piston system that uses air pressure to create a stronger force. It’s a harder hit than a hammer drill, and there are less strikes. We’ll talk more about the technology in another article. Notice that the rotary hammer is usually larger and doesn’t resemble a typical drill whereas the hammer drill looks just like a drill. You also never use a rotary hammer to drive fasteners, whereas a hammer drill can do double duty.