A hammer drill is a tool used to drill holes or insert fasteners in very hard or dense surfaces. While a traditional rotary drill would break when used on these tough objects, a hammer drill can produce higher levels of force to break down the object as needed to drill the hole. These tools are frequently used with masonry materials such as concrete, brick, and stone.
The primary difference between this tool and a regular drill is that the hammer drill has a movable chuck, the part of the drill that holds the bit in place. The chuck is capable of moving forward and backward over a very small distance, which helps to "hammer" or "kick" at the wall as the drill spins. Though it only has a short range of movement, the chuck moves very rapidly, allowing it to hammer into the walls hundreds or thousands of times per minute. This hammering motion helps to break down the stone or masonry so that the drill bit can enter successfully. The strength and power of a hammer drill is generally measured in Impacts per Minute (IPM), which represents the number of times the chuck can hammer into the wall each minute.
These tools are often used in applications where workers need the combined benefits of a hammer drill and a regular rotary drill. The unit is usually equipped with a switch that can turn the hammering motion off as needed, which means that the chuck will remain stationary for use in traditional drilling applications. A hammer drill is a convenient option for workers going into a job where they are unsure what surfaces they will be working with, or where they will need to drill into both wood and stone objects. Buyers can choose from units with electrical power cords or more flexible battery-operated versions.
The hammer drill is often confused with a similar tool known as a rotary hammer. The rotary hammer is a heavy-duty version of the hammer drill, and is capable of creating large holes at a fast pace, even in very dense or hard materials. It uses a piston mechanism that is similar to a jackhammer, and may also include an integral weight that helps the piston drive the drill bit more firmly into the surface. These units require special bits that can be locked into the chuck, as regular smooth bits generally won't stay in place. In addition to drilling holes in masonry surfaces, rotary hammers can also be used for chipping or chiseling stone or concrete.