Guide written by:
Jeremy, construction site supervisor, Cardiff
Got some masonry jobs in the works? If you're looking for a drill that offers heavy-duty hammer action, then a rotary hammer is the tool for you! From corded to cordless models, we'll take you through the various options including chuck type, impact energy and motor power. Read on to find the ideal rotary hammer.
- Power rating
- Blows per minute
- Rotational speed
- Rotary hammer
Choosing a rotary hammer based on usage
If you only have a few holes to drill and/or a job that won't take too long, go for an SDS hammer drill able to deliver an impact energy of 3 joules, 3000 blows per minute and 900 W. This type of model will be perfect for removing a few tiles and squaring off or levelling out brickwork. With a maximum speed of around 800 RPM, you'll also be able to drill about 26 mm into concrete, around 13 mm into steel and up to 40 mm in wood. Go for a model equipped with auto shut-off for increased safety. A low-end hammer drill will set you back about £50 to £65 and will usually offer a warranty of about a year.
Plan on drilling a 26 mm hole into reinforced concrete? Want to level out a row of bricks or make a hole in a wall? If you plan to use your rotary hammer for light demolition work on a regular basis, opt for a model that offers 4 to 6 joules, 4300 blows per minute, and a power rating of about 1500 W. A maximum speed of 900 RPM will allow you to drill up to 32 mm in concrete (according to the model), 40 mm in wood and 13 mm in steel. If possible, choose a model equipped with an anti-vibration handle and auto shut-off. Expect to pay around £80 to £100 for a mid-range tool with a 2-year warranty.
Are you a building professional? Do you plan on carrying out heavy-duty masonry work and using your drill every day in both drilling and hammer mode? There's no doubt about it: you will need a rotary hammer from a professional brand. This way, you will get a 2- to 3-year warranty (with the option to extend), great after-sales care and a robust drill. In terms of features, your choice will come down to the types of jobs you plan to do, bearing in mind that the higher the impact energy in joules, the more powerful the hammer mode. A rotary hammer with around 8-10 joules, 3000 RPM and 1200 W will be versatile enough for anyone planning to use the tool on a daily basis. It's worth noting that you can invest in a much more powerful rotary hammer with over 20 joules. However, these are best suited to heavy-duty demolition work. The maximum drilling diameter can be found in the product description and this should be weighed up with your needs in terms of hammer action. If you need a drill for regular and prolonged use, go for a lightweight rotary hammer with an anti-vibration system, an auto-stop clutch and a variable speed drive. So, how much will all that set you back? In short, you shouldn't expect to pay less than around £200.
Cordless rotary hammers
If you're looking for a cordless rotary hammer, you'll have to pay attention to voltage (V) (which indicates battery capacity) and ampere hours (Ah) (which indicates battery life). The higher these ratings, the better the performance and the longer the tool will last between charges. If you find yourself comparing two models, go for the one with a higher Ah rating. It's also worth considering a model that comes with 2 batteries rather than one, to ensure continuous operation. In terms of battery technology, Lithium-ion (Li-Ion) is generally the market standard for power tools these days.
Rotary hammer applications
Rotary hammer components
To the untrained eye, it can be tricky to tell the difference between a standard drill and a rotary hammer – especially when it comes to lightweight models. The tools do look similar, yet there are many differences between them, in terms of both application and performance.
Two main applications of a rotary hammer
- Designed chiefly for masonry work, rotary hammers are able to drill into concrete walls with no problem. Used in drilling mode, a rotary hammer will also have no issue drilling holes in wood, metal and can even be used to tighten and loosen screws!
- In hammer (or percussion) mode, a rotary hammer is able to handle a range of small demolition tasks such as removing tiles, making holes in walls, and so on.
How does a rotary hammer work?
Rotary hammer modes
Hammer mode with rotation: a concrete drill bit hammers through the surface and clears out the dust as it rotates. This mode is used to drill large holes into a range of materials, and is pretty much what these tools are designed for.
Hammer-only mode: this refers to hammer mode without rotation. Chisel bits can be used for light demolition work; be sure to pick the right size of bit according to the amount of power your tool can deliver. Furthermore, it's worth noting that a rotary hammer will usually only offer two modes (rotation and hammer and rotation mode). Hammer-only mode can usually only be performed by more powerful rotary hammers.
Electric vs. pneumatic rotary hammers
Electric rotary hammers
Electric rotary hammers are designed to handle a range of DIY tasks. The percussion mode of these drills is performed mechanically and these tools will rarely have an impact energy of more than 10 joules. Lightweight and easier to handle, these drills are better suited to at-home use.
Pneumatic rotary hammers
Pneumatic rotary hammers are best suited to heavy-duty work such as demolition tasks or other intensive use. The hammer mode of these rotary hammers is driven by air pressure created by a piston. These tools can easily deliver 30 joules.
Corded vs. cordless rotary hammers
One of the first questions you'll want to think about when choosing a tool is its power source. Once again, it all depends on what jobs you want to do!
Corded rotary hammers
As long as you keep paying your electricity bill, you can keeping drilling for as long as you want! More powerful than cordless models, corded rotary hammers are designed to carry out bigger tasks, such as drilling into very hard surfaces like concrete or stone.
Designed for more intensive use, these tools can also be used for light demolition work. However, the presence of a cord will limit your movements and you will have to invest in an extension cable if you want to work outdoors!
Cordless rotary hammers
A cordless rotary hammer is perfect for small job sites with no electricity. However, they do offer limited impact energy (usually less than 3 J), and won't be able to drill into any particularly hard materials. Cordless drills are also unsuited to any task involving prolonged drilling, even occasionally or on a smaller scale. That said, high-end battery-operated rotary hammers will offer similar specs to some corded models.
Rotary hammer features
Whether you go for a corded or cordless model, here are a few technical features to consider, depending on your needs and the types of jobs you want to carry out.
One of the most important specs to think about is impact energy, which is indicated in joules (J). Impact energy basically translates into efficiency and will determine how well your rotary hammer performs. The more joules, the harder the blow! A drill with 3 J will be more than capable of handling a range of small tasks on a less frequent basis. For heavy-duty applications (such as professional use or demolition work), you'll need to look for a model with over 5 J.
Blows per minute
The impact rate of a rotary hammer is given in blows per minute; pay attention to this spec if hammer mode is particularly important to you.
Revolutions per minute
It's important to consider the number of revolutions per minute (RPM) as this determines the tool's ability to drill into certain materials. Rotary hammers usually feature a slower rotational speed than standard drills, but should still ideally offer around 300 to 1000 RPM.
Rotary hammer modes and applications
It's important to identify your needs before you start looking for a rotary hammer as not all models will offer three modes (i.e. rotation only, hammer only, rotation and hammer). If you don't plan on doing any demolition work, you can probably rule out the need for a hammer-only mode (which, as mentioned, is usually only provided by a rotary hammer). Rotary hammer kits usually come with a range of different wood and metal drill bits, chisels and spades for different tasks.
Rotary hammer chucks
Rotary hammer are usually equipped with special quick-change, keyless chucks: namely, SDS+ chucks and SDS Max chucks. These chucks allow you to insert bits directly, without the need for any screwing or keys. Simply apply a spot of grease to the bit shank and click it into place! SDS+ chucks generally come as standard. These chucks are featured on most rotary hammers and it is easy enough to find a good range of SDS+ bits for your tool. However, the maximum drilling diameter will be around 30 mm. SDS Max chucks are generally only featured on rotary hammers from professional ranges offering a lot of power. SDS Max drill bits are harder to find and therefore more expensive. However, they offer a drilling diameter of up to 52 mm! Some rotary hammers feature an interchangeable chuck, which is ideal if you want to use straight shank bits.
Rotary hammer batteries
If you go for a cordless rotary hammer, you'll have to choose between several types of battery. The voltage of the battery will vary and this can go up to 36 V for higher end tools.
In order to make the right choice, you'll have to think about the battery voltage. The higher the value, the longer you'll be able to work at top speed. While the ampere/hour (Ah) rating indicates battery life, voltage refers to the battery power. To keep things simple, you should aim for around 18 V and 4 Ah. In terms of battery technology, you have a choice of three materials, but bear in mind that the first and third options are relatively rare.
- Ni-cd : nickel cadmium, a fairly outdated choice. These batteries are heavy, take forever to charge (as a general rule) and have a memory effect.
- Lithium-Ion, the most efficient option. These batteries are lightweight, quick to charge and don't have a memory effect. The only downside is that they are expensive. Nonetheless, these batteries are used for most cordless rotary hammers.
- Ni-Mh or nickel metal hydride battery. These batteries are pretty heavy, but don't really have a memory effect. They do, however, age very badly and are not commonly used.
Additional features for rotary hammer
Even in the midst of a demolition project, comfort should still come first! Rotary hammers are generally loud and heavy tools that also vibrate. If you're hesitating between a few different models, go for the lightest and quietest model with vibration control. Some high-end rotary hammers are equipped with an anti-vibration system or are specially designed for quieter operation.
Key accessories for rotary hammers
Drill bits and chisels
Just like for any other tool, rotary hammer accessories differ in terms of quality. It's a good idea to try to find the best value for money and to be sure to sure to pick out the best accessories for your needs. The most basic accessories are as follows:
- concrete drill bits and wood drill bits with SDS shanks;
- pointed chisels: a type of chisel with a pointed end;
- flat chisels: come in a range of lengths and widths to match your job;
- gouges: to tidy up the edges of chases;
- quick change chucks: to change from an SDS to another keyless chuck (handy if you want to use a straight shank drill bit).
Drill bits for wood
How to choose the right rotary hammer
Comfort and safety features
- Auto shut-off: this essential feature cuts off the rotary hammer if the drill bit becomes stuck. This helps to prevent accidents and stops the motor from overheating.
- Depth stop: allows you to adjust the depth of your drilling with precision.
- Built-in LEDS: directs light onto the tip of the drill bit; ideal for working in dark areas or tight corners.
User tips and required PPE
Remember: safety comes first! When working with a rotary hammer, always wear gloves and safety glasses, no matter where you are. If you plan on using the tool for any length of time, ear defenders or ear plugs will always be welcome. When performing demolition work, wear a protective helmet and safety boots to avoid accidents. And don't forget to consider the weight of your tool: even the most lightweight rotary hammer on the market can lead to joint injuries with sustained use.
Guide written by:
Jeremy, construction site supervisor, Cardiff, 133 guides
Electrician by trade, I first worked in industrial estates where I installed, wired and fixed a large number of electrical installations. After this, I managed a team of electricians for this type of work. 10 years or so ago, I turned to building and construction. From the modest family home, to gyms and theatres; I have been able to coordinate, audit and organise all sorts of construction sites. for 4 years now, I am restaoring and bulding an extrension to a bungalow in the heart of the welsh countyside. My experience in manual work and my knowledge means I am proud to be of service. Terraces, interior design, roofing, plumbing, electricty, anything goes! We have, my wife, daughter and I, built almost everything we have from scratch! So to answer all of your questions, and to orientate and advise you on coosing your tools? Easy!