Hammer Drills can also be called a roto hammer or a rotary hammer drill; these devices are drills with a rotating hammering action. They work by providing a hammering action, a short rapid hammer thrust, which pulverizes hard brittle material, thus producing more efficient and faster drilling with much less effort. These drills are usually lower powered units, while higher powered devices are generally known as rotary hammers and are used to deliver much higher impact forces.
Most of today's drills allow use of both the hammer action and the rotatory action separately or even a combination of both, depending on the material to be drilled. They were invented in 1975 by James D Smith, who was a stonemason. These types of drill are very efficient for drilling holes in brick, concrete, sandstone and some types of rock. The hammering action chips away / breaks up the masonry and the drill flutes transport the debris away.
There are many different makes and models, prices can range from just a few pounds for a simple model which may be ideal for the home DIY enthusiast, up to many hundred of pounds for more serious use and applications ie; building industry and automotive industry.
Hammer drills can be either cordless or mains powered. Mains powered drills require some type of external power supply, either mains power or power generated by some type of electrical generator which are usually mobile.
Cordless power hammer drills carry their own power supply in the form of a battery which is usually fitted onto the end of the drills handle. With today's technology and the advancement in battery design and performance, cordless power tools have become a very attractive alternative to the more conventional mains powered power tool and can provide many hours of use. This has made them extremely popular in the public and commercial markets.
Hammer drills can have several different features incorporated into them. These features may include:
- Switchable hammer action (the drill may be set from normal action to hammer action)
- Clutch (this enables a slipping action should serve the drill bit encounter any difficulties; for example, get stuck or jam up).
- Adjustable clutch; this enables the correct torque when using the drill for driving screws.
- Reversible switch
Another type of hammer drill uses a rotary action, and these types of drill are known as rotary hammer drills. The rotary type uses a piston mechanism instead of a special clutch which allows them to deliver a much more powerful hammer blow.
Hammer drills use a specially designed clutch which allows it to punch (hammer) and spin at the same time.