I had to do a little re-planning, which had to disassemble some parts of the wall, some time ago. I even still remember the effort with a hammer. I had a lot of work over that task, because I had no mechanical devices. However, such work can be done much more efficiently and faster if you take an electric rotary hammer assistant. Let’s talk about rotary hammer choosing.
What is an electric rotary hammer? Rotary hammer is a power tool which designed for punching of holes in hard materials through the use of firing mechanism.
The structure of rotary hammer includes such basic elements as electric motor, transmission gear, hammer mechanism and cartridge which are attached with certain functional rotary hammer attachments. All these elements are located in the case, which has a special handles and control buttons.
The principle of rotary hammer operation provides the destroying of the processed material structure as a result of translational or rotational motions of the working element.
Here are the main characteristics of rotary hammers:
1. Rotary hammer power.
Electric power plays a major role in determining of the capabilities of this instrument, because hand rotary hammer is mainly used for punching of holes or damage hard surfaces.
Modern rotary hammers power can be in the range from 450 to 2000 watts. There is no clear division into categories, but it can be roughly said, that tools with power up to 900 watts are the household rotary hammers and tools with power more than 900 watts are the professional rotary hammers.
If you need to penetrate thick walls – buy a powerful rotary hammer with 1500 watts power.
Accordingly, if you are not professionally engaged in repairs, you can choose a good rotary hammer with 750-900 watts power. If you need every six months to make a hole in something, you can buy 550 – 600 watts electric rotary hammer.
2. Rotary hammer type.
There are two basic types of rotary hammers depending on the features of its engine location in the case – horizontal and vertical.
Engine locates parallel to the impact axis in the horizontal rotary hammers.
In vertical rotary hammers engine is placed perpendicular to the impact axis, so such tool is similar to the inverted English letters L. Such rotary hammers are also called L-type rotary hammers.
Horizontal drills are more convenient to work in narrow slots, because they are more elongated and narrow. Majority of consumer rotary hammers are horizontal.
Vertical rotary hammers have the advantages in terms of cooling of their motor and their power, so most professional rotary hammers are vertical.
3. Impact power.
Rotary hammer impact power shows which energy carried in rotary hammer interaction with the work piece.
From this figure depends on the efficiency and speed of the tool. It is measured in joules and directly proportional to the electric power.
For example, rotary hammer Bosch PBH 3000-2 FRE with electric power of 750W has 2.8 J impact power and can make holes in concrete with a diameter of 26 mm and a large.
Rotary hammer Makita HR 5211 C with electric power of 1500W has 20 J impact power and can do up to 52 mm diameter holes in concrete.
Average for everyday use, you can choose models with impact power drills 2,6-4,5 J.
4. Number of modes.
Besides the basic functions of punching, rotary hammer may have other, depending on how many operation modes it provides.
Most often you can find these rotary hammer modes:
- Drilling. In this mode rotary hammer does not differ from the conventional electric drills. You can use rotary hammer in this mode to make holes in a relatively soft material, such as wood.
- Drilling with a punch.Rotary hammer performs circular and translational motion simultaneously in this mode. This is the main rotary hammers mode. It is used to make holes in hard materials.
Many electric drills also have the function of drilling with a punch.
There is the question: what is better impact drill or rotary hammer? There is no a definite answer to this question, because these instruments have a different principles. A drill is the best for drilling in a relatively soft material, while rotary hammer helps to make holes in hard surfaces (i.e. drilling into concrete). Bay the way, if you don’t know how to drill in concrete – use rotary hammer, this power tool will help you to make holes in concrete vary quickly. But if you want to drilling stainless steel you need to use a simple drill, not rotary hammer.
- Impact mode. Rotational movements of the working elements are missing, and there are only impacts in this mode, such rotary hammer can be used as a jackhammer.
Buyer needs to pay attention to the number of supported by the instrument modes. There are one-, two- and three-mode models that support respectively one, two or all three modes.
It’s best to buy three-mode rotary hammers, which can be used for different purposes.
5. Cartridge type.
Cartridge is a device for attaching working attachments (drill, drill, bits, chisels or other). Now the most common are the two types of drill cartridges SDS plus and SDS max.
Cartridge SDS plus installed on most household rotary hammers, they may be used for holes with a diameter of 15 mm.
SDS max cartridge intended for use in professional models, they can be mounted for large diameter bores (often 26 mm).
6. Rotatiol speed and impacts frequency.
Rotation speed and impacts speed indicates how many rotational and translational movements make your drilling hammer per time unit.
Rotation speed of rotary hammer can be from 230 to 2300 rpm. Small household rotary hammers have higher rotation speed (about 1500-2000 rpm) and professional rotary hammers have lower (about 230-450 rpm).
Impacts frequency can be from 2150 to 5800 beats per min.
For normal household rotary hammer use can be recommended model with rotation speed 1000-1500 rpm and a frequency of impacts 4000-4500 beats per min.
7. Rotary hammer weight.
Weight of hand tools plays a significant role in their choice. Rotary hammer choosing is not exception, because of this indicator depends how long you can work with it.
Rotary hammer weight can be from 2.2 to 12 kg, depending largely on its power.
Light drills are considered up to 3 kg, medium – from 3 to 5 kg and heavy – more than 5 kg.
Good household rotary hammer weighs approximately 2,6-3,3 kg.
8. Additional Features.
In addition to the major, you must also pay attention to the additional rotary hammer features, such as:
- Speed switching controller. It helps to determine the speed of the rotary hammer, according to the specific work.
- Reverse. It allows you to move rotating element in the opposite direction that makes it easy to pull the bit out.
- “Soft” descent, soft descent system helps prevent sudden jerks when the instrument works, as in angle grinders.
- Anti-vibration system. Helps reduce the negative effects of vibration to the operator.
- Stopper switch. This is a special lock that helps to prevent permanent holding the switch with your finger.
- Coupling for protection against jamming of the drill. It protects the engine and the operator in the event when the working drill gets jammed. Rotary hammer manufacturers tries to install this coupling at almost all products, but check its presence can not hurt.
- Vario-lock system. This system helps to change the angle of the tool’s working plane.
The presence of each of these features is a big plus for choosing a hand rotary hammer.