What to expect from this article
Sales rankings change, and they say little about whether a tool fits your job, so this article names no models. It covers the specifications that matter when a corded rotary hammer is used mainly for breaking and chipping, so you can compare any candidates on equal footing.
Hammering versus breaking
A rotary hammer uses an electropneumatic mechanism: a piston drives a striker that hits the back of the bit, while the bit can also rotate. In drilling modes, rotation and hammering work together to bore holes in masonry, as described in hammer drilling masonry.
For demolition you want the tool to hammer without rotating. That is chipping mode, sometimes called hammer-only. With a chisel or point in the chuck, the tool breaks concrete, removes tile or thinset, or chases a groove. Most models have a mode selector, though lighter ones may not offer a true hammer-only setting. If breaking is the main job, confirm that it does.
Impact energy
Impact energy is the force of each blow, usually given in joules or foot-pounds. Higher numbers generally mean faster material removal, but they also mean a heavier, more tiring tool.
Roughly speaking, lighter SDS-Plus tools suit drilling and light chipping, while larger SDS-Max tools, and heavier ones above them, are aimed at serious breaking. The exact figures vary widely and are measured under different conditions, so treat them as a class guide, not a precise ranking. Also look at blows per minute, since a tool that hits very hard but slowly can feel different from one that hits a little less hard more often.
SDS bits and shank sizes
SDS shanks have slots that let the bit slide back and forth in the chuck, so the hammer’s blows reach the bit without the full hammering force being absorbed by the chuck. The two common shank types are not interchangeable:
- SDS-Plus has a smaller shank and suits holes and light chiseling.
- SDS-Max has a larger shank and suits heavy chiseling and large holes.
The chuck type is part of the tool, so decide on a class first. Unlike ordinary drill chucks, SDS chucks are tool-specific. For breaking, you will typically use several bit shapes:
- Points concentrate force to start breaking.
- Flat chisels clean off surfaces and cut edges.
- Wide or scaling chisels remove tile or thin layers.
- Spade or gouge shapes are used for trenches and channels.
Bits wear and can lose their shape, so inspect them for cracks or mushrooming before use. Quality varies, and a poor chisel can waste the tool’s power.
Features worth checking
- Weight. Breaking is often done at an angle or overhead, where weight quickly matters.
- Vibration control. Many designs include a damping handle or counterweight. Long sessions with strong vibration are tiring, so this feature is more than a luxury.
- Variable chisel positions. Some tools let you lock the chisel at set angles, which helps with angled work.
- Overload clutch. If the bit binds, a clutch protects the gearing and reduces wrist strain.
- Cord length and quality. A longer, heavy-duty cord reduces the need for extension cords, which must be sized properly. Good power cord care and regular inspection matter on a tool that vibrates.
- Amperage. Higher amperage generally indicates a more powerful motor, though not a guarantee of output. See tool amperage for how amps and power connect.
- Service availability. For tools that work hard, easy access to brushes and replacement parts keeps them running.
Corded versus other options
Corded models give consistent power for as long as the work continues, which is why they remain common for sustained breaking. Their drawbacks are the cable and the need for a suitable outlet. If the site has limited power, remember that portable generators have to be sized for the tool’s starting load. Check the manual for guidance.
Safety for demolition work
Concrete dust can contain crystalline silica, which is hazardous when inhaled. Use a respirator rated for fine dust, water suppression or dust extraction where practicable, and keep bystanders away. Beyond dust, wear eye protection and hearing protection; rotary hammers are loud and long exposure can damage hearing. Gloves and sturdy footwear are sensible too.
Before cutting into any wall or slab, find out what is behind and beneath it. Hidden electrical lines, plumbing, gas or rebar can make breaking dangerous. Unplug the tool before changing bits or modes. Further background is in demolition tools and basic precautions, and structural or load-bearing work calls for a qualified professional.
Choosing sensibly
Decide how much breaking you will do. For occasional chipping, a mid-size SDS-Plus tool with a hammer-only mode may do. For regular slab or wall work, an SDS-Max class tool is typically the more realistic choice. If you only need it for a day, renting is a reasonable way to avoid buying more tool than you need. Whichever you consider, compare impact energy, weight, vibration control and the bits you will actually use.