In this article you will learn everything you need to choose a rotary hammer drill. First of all, we need to thoroughly explain the differences between rotary hammer drill and conventional drills. Other essential parameters are mainly type, power, design of the structure, number of revolutions and impact force. These are crucial for the proper functioning of the device and its endurance. On the other hand, the user experience is mainly influenced by weight. You should choose a device that you will handle well. We will also evaluate various additional functions and their usefulness at work. Last but not least, we must not forget the type of chuck, because even in this case you can use a wide range of drills designed for different tasks.
There must also be a chapter dealing with prices. In it, we divide the offered products into price zones according to how skilled tradesman they are intended for. Of course, we will evaluate what you can expect for each amount of money.
How to choose a rotary hammer briefly:
- Select the type of hammer according to the power supply method. You can choose between more powerful versions powered by cable, and more mobile battery variants, which tend to have slightly weaker performance.
- Explore rpm and power. These parameters play an important role in drilling. The harder the work you need to perform, the more powerful a hammer you need.
- Consider the impact force, which determines the rate of penetration into the material. It is given in joules. For home use, you can make do with an impact in the range of 1.5 to 3 J.
- Look at the chuck. Lighter hammer drills use the SDS-Plus system, a professional SDS-Max that is compatible with larger drill bits.
- Let it not be unnecessarily heavy.Especially if you hold the rotary hammer in one hand, it should weigh no more than 3 kilograms.
- Be interested in additional features and add-ons. To come with a rotary hammer, you need compatible drill bits. Speed and impact control can also come in handy.
- Choose a suitable price range and choose several candidates. In particular, a hammer for home use may not cost you more than £200. Check out the user reviews, because they will tell you a lot about the qualities of the product.
Hammer or Drill?
Looking at the drill and hammer drill in the store, it may seem that they are one and the same. Do not give the first impression, because both devices are fundamentally different. Both by the design and the purpose of use.
Conventional drills are characterised by a higher number of revolutions (about 3,000 per minute) and application when drilling in soft materials. It can handle plastic, wood or metal without major problems, more expensive models with impact drill their way through stronger aerated concrete. If you are looking for powerful drills, take a look at the electric impact types, but there are also cordless drills available on the market, which combine many advantages with good mobility.
Rotary Hammer Drills
But what if we have a piece of solid concrete in front of us, properly reinforced with iron? You probably realised that in that case the rotary hammers would get the space. Although they have a lower speed (about 1,000 per minute), they use a much stronger impact that allows them to penetrate harder material. The overwhelming force of multiple blows will help disrupt even massive materials.
Corded Hammer Drills
Time-tested classics are devices that are connected by cable to the power grid. When using them, you do not have to worry about the state of the battery and the device is immediately ready to work. The advantage is also lower weight due to the absence of a battery. They are used both in households and especially in professional operations. Compared to battery models, they maintain a clear lead in performance. Therefore, you do not have to worry that you would not be able to cope with a solid piece of concrete. Perhaps only the power cord can sometimes unnecessarily interfere.
Cordless Hammer Drills
For less demanding users requiring primarily mobility, battery products are intended. You can take them with you virtually anywhere and they work even without being connected to a power source. You just have to pay attention to the regular recharging of the battery. Unlike corded hammer drills, however, be prepared for higher weight and especially lower power, which is closer to the rather expensive impact drills. Also, keep in mind that as the battery decreases, the drilling efficiency and speed decreases dramatically.
An absolutely crucial parameter that indicates the real power of the tool is power. The basic unit of power is watt (W). The power consumption is closely related to the power, the value of which in turn reflects the amount of energy consumed. The two parameters can never be equal, because part of the power is used to ensure the operation of the device. In general, the higher the power, the more powerful the material can drill through. For normal household use, 600 W is fully sufficient. However, if you want to drill, for example, in a panel apartment, you should choose a device with a power of at least 800 W. It is optimal to choose a hammer with a sufficient margin. So that you do not work unnecessarily and mainly reduce the overheating of the engine. Professionals should look for products above 1,200 watts.With such a force, the machine can easily cope with reinforced concrete or marble. On the contrary, in no case do not buy cheap models with a power below 400 W. The level of their work will be even worse than that of classic impact drills due to lower speeds.
Other key attributes also include the design of the structure. Ergonomics play a major role, making it easier to hold the tool while working, as the hammer is not very easy to handle. The handle should fit perfectly in the hands of right- and left-handers. In addition, it should definitely eliminate or at least significantly dampen the vibrations that arise during drilling. Definitely take into account the materials used in the manufacture of the structure. Significant is their resistance to mechanical damage, usually it is a very robust combination of plastics and sheets. The engine should be protected against dust clogging. Do not forget about the location of the centre of gravity. Few things can make handling a hammer more difficult than when you have a heavy hammer when you’re working.
Do not count on the fact that the amount of revolutions of the hammer drill will be similar to that of conventional drills. Everything is mainly due to the dimensions, which in the case of the hammer are significantly larger. Turning the drill bit too quickly would break the surface to be worked. Ideally, expect a maximum of around 800 revolutions per minute. The larger the machine in your hand, the slower it will rotate, of course. The number of revolutions should also correspond to the amount (strength) of hammers.
The key parameter is the hammer force measured in joules (J). The impact force is affected by the amount of air that the pneumatic piston can press. The higher it is, the more efficiently and faster the device penetrates the material. As in the case of power, the size and weight of the hammer also increase as the impact force increases. Always choose products with pneumatic impact. A piston with compressed air makes handling much easier. You will achieve a higher strike force using a lower mechanical force. For simple work, an impact of about 1.5 J is sufficient.Professionals are then assigned equipment capable of generating a force of 6 to 12 J per stroke.
Slotted Drive System
Do you still have an old drill at home with the old shank system of holding a drill bit? Then know that this system is gradually disappearing and is being replaced by SDS drills. This is the so-called SDS mechanism, which, in addition to easy and quick of the drill, also guarantees optimal energy transfer. Currently, we distinguish two basic methods of SDS chucks:
The mechanism for lighter hammers and can hold smaller and thinner drill bits of a diameter of 10 millimetres. In addition, it is fitted with grooves to increase drilling efficiency and prevent unwanted spinning of the drill. This type allows you to fix drills in the range from 4 to 32 millimetres. It is always necessary to select special sets compatible with the SDS system.
Hammer drills of heavier weights rely on the SDS-Max slot mechanism, which is suitable for drills with a diameter from 12 to 52 millimetres. The slot shank has a diameter of 18 millimetres and is equipped with three grooves. In the category of hobby tools, you will hardly encounter this system, as it is mainly used for tools for professionals. For this reason, this method is more expensive. It is also necessary to count on the fact that you will pay extra for compatible drills.