For someone unfamiliar with power tools, a drill is just a drill. The reality, though, is that just like there are various types of cars and other everyday products, there are also various types of drills.
When it comes to working with concrete and other harder materials, the two most common types of drills are hammer drills and rotary hammers. Continue reading to learn what the differences between the two are and which one will work better for the job that you need to get done.
Hammer Drills and Rotary Hammers: The Basics
Before trying to figure out which of the two tools is the right one for your job, let’s start with the basics – by looking at what each of the tools is.
What Is a Hammer Drill?
A hammer drill is a drill that is specially designed to not only spin the drill bit, but to also punch it in and out. It can deliver thousands of blows per minute (BPM), helping the drill bit cut through extremely tough materials like concrete, stone or brick.
The tool is not designed for driving screws in (although it can do so) like an impact driver is, but for producing a hole much faster than a conventional drill.
What Is a Rotary Hammer Drill?
Rotary hammer drills are hammer drills that use a piston and a rod to hit against the drill bit, which amplifies the effect of the power and therefore makes rotary hammer drills more powerful than their regular counterparts.
This rotary mechanism makes this type of tool much more efficient at creating holes than a normal hammer drill. That mainly applies to materials that need “breaking” like concrete, bricks, etc.
A 7.0 amp corded rotary hammer accepting SDS Plus bits.
A 7.0 amp hammer drill with a 1/2-inch chuck.
Hammer Drill vs. Rotary Hammer: What Are the Differences?
Now, let’s take a look at some of the main differences between the two tools.
While both tools move the bit back and forth while it spins, the two have different mechanisms for achieving this.
In a rotary hammer, a cylinder of air is compressed by a piston driven by a crankshaft, which in turn pounds the bit. The piston rides in a cylinder and creates air pressure when driven forward, and it’s the air pressure that actually drives the hammer mechanism.
Thanks to that, rotary hammers provide a lot more impact energy than hammer drills.
In a hammer drill, two ribbed metal discs come together and move apart, causing the impact. This is a fast but shallow impact action that operates at a high speed of up to 30,000 per minute.
Among tradesmen working daily, rotary hammers are preferred because of their superior strength and shock-absorbing qualities. For the occasional user, the large, bulky tools are overkill. In that case, a powerful all-purpose drill driver with a hammer-drill setting makes more sense.
Rotary hammers are never used to drive fasteners, but a hammer drill can be used for both driving screws and drilling holes. Rotary hammers, on the other hand, generally have three settings: drill, hammer drill or just hammer. The last of those lets the user use it as a mini jackhammer.
Because of those differences, a rotary hammer is usually fairly large, while a hammer drill is smaller and resembles an ordinary drill. The larger size of the rotary hammer makes it better suited for professionals who need a heavy-duty impact drill for making a large number of holes in hard materials regularly.
Attachments and accessories
Both rotary hammer drills and hammers drills require a different set of attachments, such as chisels, drills, and spades.
Let’s look at some accessory options for rotary hammer drills. When set to hammer mode, rotary hammers can be used for all sorts of jobs, and there are a whole lot of attachments to get those jobs done. A few of the more popular attachments are:
- Clay spade for breaking up hard soil.
- Cold chisel for busting up concrete.
- Tile remover for pulling up and removing ceramic tiles.
- Bull point chisel for starting holes in concrete.
- Scaling chisel for removing rust, concrete, and weld spatter
Some accessories of those accessories require a certain type and size of chuck.
SDS-Plus is the most popular type of hammer drill chuck today. SDS-Plus bits have grooves on their shanks that lock securely into the chuck but allow the bit to move back and forth independently of the chuck.
These bits are easy to insert and remove, and no tools are required. Chucks larger than the SDS-Plus are called SDS-Max. Keep in mind that there are a few brands that have proprietary systems, so match the chuck type to the attachment you need to use.
In case you want to use your rotary hammer to bore large holes in wood or mix joint compound, consider buying an SDS-Plus chuck adapter. This adapter accommodates smooth-shank drill bits, hole saws and mixing paddles. When using the adapter, always keep the setting on drill mode to prevent it from breaking.
A three-jaw chuck may also be used for regular drill bits.
All-metal chucks are more durable than ones with plastic parts. And, while keyless chucks are handy on a regular drill, they often don’t have the holding power needed for drilling into masonry. Chuck size often dictates the maximum recommended hole size that a drill can handle.
Finally, rotary hammer drills and hammer drills have different impact energy. A rotary hammer’s pounding energy is measured in pounds of impact energy. For a rotary hammer, higher amp power is good, but more impact energy is even more important.
A tip worth noting is to buy a drill capable of drilling larger holes than what you require. That way it won’t have to work at its maximum capacity all the time.
Which of the Tools Is Better?
They’re both different, but if you want to drill 3/8-inch or larger diameter holes in masonry, drill through rebar, or break up concrete, then use a rotary hammer (or even the larger demolition hammer).
If you want to use the drill for light carpentry, maintenance, or DIY work – and drill the occasional small hole into concrete – a hammer drill will be sufficient.
The hammer drill will be less expensive than the rotary hammer, but it is also less versatile when it comes to working with harder materials. It can be used for wood or masonry whereas the rotary hammer will accept bits for hard clay, tile, chiseling, and more.
You might find the hammer drill being knocked off course by heavy aggregate while the rotary hammer will drill steadily through concrete.
As you can probably tell by now, a hammer drill is a general, multi-purpose tool. It’s designed to be able to drill into concrete and other such materials to a certain extent, but it’s also universal enough to work with wood and other materials.
A rotary hammer, on the other hand, is a tool specialized in working with concrete, hard clay, and other similar materials. It’s considerably more powerful allowing for drilling larger holes into harder materials. It also oftentimes has a “hammer mode” which allows for the tool to be used as a jackhammer.
All in all, if you are a homeowner that needs to drill into concrete every now and then, you are better off getting a regular hammer drill. On the other hand, if you are a professional builder working on heavy-duty construction sites, getting a rotary hammer – or both – might be a better option.