- The screwdrivers: a mechanism made to "shock"
- Rechargeable at any time
- Getting started with the tool
- Battery and charger of screwdriver
- Our test bench of six cordless impact drivers
- Test results of screwdrivers
- Comparative table of six impact screwdrivers
Compact and lightweight, this tool is a concentrate of power! Thanks to the tightening torque, it allows difficult screwing and unscrewing without fatigue for the user. A good companion for many DIY activities...
The "shock" wrench (also known as a "wrench"), which is widely used in mechanics and most often with compressed air, has seen its mechanism evolve over the last few years towards a cordless power tool that is easier for users to use. yourselfers.
The screwdrivers: a mechanism made to "shock"
The impact screwdriver screws or unscrews the most recalcitrant bolts, screws or bolts. Very easy to handle, the tool does not require any particular adjustment.
It is equipped with a hexagonal mandrel mandrel, a trigger that allows to measure the speed of rotation of the motor and a reverser of direction. Its lithium-ion battery is housed at the base of the handle (Dewalt) or inside, which ensures the proper balance of the screwdriver.
To obtain the striking force equivalent to that of a pneumatic impact wrench, the cylinder is replaced by an electric motor extended by an "impactor", a kind of hammer provided with a spring that hits an anvil fixed on the mandrel. When the force to drive the screw exceeds the motor torque, the hammer spring causes the anvil to hammer repeatedly (thousands of times per minute) and provides a large torque (three to four times superior to that of a cordless drill).
The tension of the spring determines the force of the work and the percussion of the tool. The more the spring is stretched, the more the impact is delayed; the less stretched, the higher the frequency of the impact. In "mode" percussion, the rotational speed of the mandrel decreases, and the screw sinks effortlessly (no need to press the tool). Advantage of this system: the end pieces remain in the footprint of the screw without skidding, which prevents their deterioration as well as that of the screw heads.
In addition, no locking of the tip can twist the wrist of the user is to be feared; a plus during repetitive screwing work. Before choosing an impact screwdriver, you must take into account the maximum torque and speed of rotation of the mandrel, depending on the work to be done and the materials used. Indeed, a very powerful device may easily break screw heads too small.
This is the power - it can exceed 500 Nm (Newton meter) - which conditions prices...
Rechargeable at any time
The screwdrivers tested here show a maximum torque of between 80 Nm (Triton) and 115 Nm (AEG) and a no-load speed of 2,000 rpm (Triton) at 2,450 rpm (Makita).
They are designed for a regular, binding and repetitive work. Equipped with appropriate bits (hex tips), they can also be used occasionally drill. Thanks to their lithium-ion battery, they are light, have a long battery life and can be recharged at any time. They do not nearly fail by unloading, but suddenly stop when empty (System D No. 794, March 2012, p.20).
The power of the battery is here between 10.8 and 12 V (AEG), with an amperage of 1.3 to 1.5 Ah: a little just for the intensive work which exhausts the battery quickly. Fortunately, the devices come with a set of two batteries (except the Stanley) and a charger (charging time of 30 to 50 min). Some manufacturers such as AEG and Triton, however, offer an optional 3 Ah battery to double the autonomy of the tools.
Getting started with the tool
The mandrel rotation inverter has three positions: two (right and left) for screwing and unscrewing; another (in the center) to lock the trigger to prevent accidental starting (on Dewalt and Stanley, it is hard to operate).
Simply pull the ring of the hexagonal mandrel to insert a bit, and release it to lock it. On the AEG and the Dewalt, you do not need to operate the ring: the tip is put in place automatically.
All models tested are equipped with LED lighting. With timer (AEG and Makita), it remains active for a few seconds once the trigger is released. The three LED lighting (AEG and Dewalt) is particularly effective.
The percussion arrives after having initiated the screwing, playing with the pressure of the trigger. Then, no need to press: the shocks force the screw by blocking the tip in the footprint of the screw head without risk of damage.
Battery and charger of screwdriver
On five models tested, the battery is housed in the handle, which makes them easy to handle. Simple to install, it is extracted with more or less resistance. On the Metabo, just press a button to unlock it.
The Dewalt has a rectangular battery located at the base of the handle. The tool is thus more stable and the handle remains ergonomic. Its implementation however requires a little dexterity.
The pictograms of the loader (supplied with the screwdriver) clearly demonstrate the progress of the loading steps. Only the charger Triton is devoid of drawings and is satisfied with two lights...
Our test bench of six cordless impact drivers
Our testsThe six tools selected are considered "small" screwdrivers, despite their tightening torque ranging from 80 to 115 Nm. Their price remains high, but the services they can provide are up to the task.
In order for the tests to be fair, we charged all the batteries to the maximum. To test the autonomy and clamping capacity of the tools, we planted screws of all sizes in a 120 x 100 mm acacia bastaing. First, 4 x 100 mm wood screws with Torx fingerprint, until the battery runs out.
A first test that heated devices and allowed to determine the number of screws depressed (Metabo and Dewalt distinguished themselves).
After letting the tools cool down, we screwed lag screws (8 x 100 mm) into the wood without pilot holes. A crucial test to finalize the classification. Ergonomics, ease of use, battery installation and charging time were also taken into account in the final assessment.
Test results of screwdrivers
After testing all the screwdrivers, two models prevailed.
- The Dewalt ranks first thanks to its lightness and strength of work that make it particularly balanced and efficient.
- Secondly, the Metabo just gives up its leading position because of its lower performance during the series screwing test.
- In third place, the AEG and Stanley Fatmax do not demerit. The first lack of endurance and the second of practical aspects.
- Fifth, the Makita has been surprisingly effective in screwing screws, but his lack of stamina makes him lose points.
- Distanced at the end of all tests, Triton, sixth, is a little disappointing. Despite this ranking, it can be interesting during occasional work...
The choice of System DThe Metabo Impact Driver (a well-known brand of expert DIYers) caught our attention for several reasons.
It is first of all its quality of manufacture and its robustness which made tilt the balance in its favor. It is also very effective for bolting or screwing screws. Other advantages, the charging time of its battery announced by the manufacturer is respected, the power present and the correct load bearing.
A little extra: the case offers practical storage compartments. A safe investment!
Comparative table of six impact screwdrivers
Click on the images below to read the details of the results of this test bench and find out which screwdriver to buy:
(Tests published in January 2014: models and prices may have changed at the time of your reading)