Power tools are often multi-functional in use but one power tool that is quite specialised in its application is the impact wrench which is focused on the undoing of difficult-to-remove nuts and bolts. Although historically the air-powered impact wrench has been the dominant form in use, mostly in the hands of professionals, in more recent times, the electric version of the impact wrench has started to find its way into the tooling arsenal of the DIYer. This is the type of impact wrench that we focus on here.
In this review of electric impact wrenches, we first look at how this power tool is used and what makes it different from other similar tools like the impact driver. Then, since you probably stumbled upon this review as part of research into buying one, we examine the different technical specifications that are present in today’s crop of electric impact wrenches with a view to establishing what to look for when purchasing one. Finally, once we have figured out what the best impact wrench is likely to look like, we then delve into actual popular electric impact wrenches that are for sale in the UK today.
The Impact Wrench for the DIYer
The impact wrench is mostly known for its use in the automotive industry, but it also plays key roles in the maintenance of other machinery and infrastructure or construction projects. In the case of the DIYer, he or she will likely buy an impact wrench also to make the changing of wheels on a car or other vehicle a breeze, but the impact wrench may also see use in the assembling or disassembling of other machinery in or around the home or in a home construction project. Impact wrenches are sometimes the only tool that will release a stubborn or seized fastener, which it achieves through the creation of a high-torque hammering action at the interface with the fastener. Since the high torque is only briefly applied with each blow of the ‘hammer’, the operator actually feels very little reactionary torque in the opposite direction making the impact wrench easy to use by anyone. In addition, the impact wrench requires a minimum resistive torque in order for the high torque hammering action to get going meaning that the tool can also be used to undo or fasten nuts and bolts that are not necessarily stuck.
Impact wrenches come in a variety of sizes with one of the most common sizes purchased by the DIYer being the 1/2” machine (the 1/2” referring to the size of the drive shank or anvil). As alluded to earlier, impact wrenches also come in different power system formats, including those that are powered by air, mains electricity or batteries. Air-powered impact wrenches are the most common form amongst professionals who usually have ready access to the more powerful air compressors needed to operate them, but even some DIYers also favour the compressed air-powered impact wrench. In more recent times however, the electric impact wrench has started to make more headway into the consumer market as it is simpler to use, more portable, and doesn't need a separate air compressor to power it. Electric impact wrenches were originally mains electricity-powered, but with recent advances in battery technology, cordless battery-powered machines have started to predominate amongst consumers. In general, air-powered impact wrenches are cheaper, lighter and have higher power-to-weight ratios than their electric counterparts, while amongst electric impact wrenches, mains-powered corded machines usually have more power output than their cordless battery-powered siblings. However, in terms of convenience of use, the opposite is usually true with cordless electric impact wrenches often being ready to use with the minimum of setup.
Impact Wrench vs Impact Driver
The impact wrench is a similar but distinct power tool from the impact driver which is used to remove stubborn screws instead of nuts and bolts. The main differences between the two impact tools are the level of torque each can output and the type of driving shank fitted onto the machines. Impact wrenches usually can output higher maximum torque than impact drivers and they have square male anvils that insert into bespoke socket sets. In contrast, the impact driver, has a female hexagonal bit holder, usually 1/4” in size, that is essentially the same as those found on other types of electric screwdrivers (and some manual ones too).
Chrome Socket Sets: can they be used on an Impact Wrench?
The simple answer to this is no, impact wrenches need their own set of special impact-resistant sockets. That’s because the use of regular sockets that are used on regular socket wrenches are liable to being damaged by the high-impact high torque action of the impact wrench since the metal they are made from tends to be more brittle. Specialised impact wrench socket sets are needed for use with an impact wrench, and they are usually black in colour as opposed to the more common chrome sockets that regular socket wrench devices use.
Can an Impact Wrench be used to fasten Nuts and Bolts?
Another common question with impact wrenches is whether they can be used for screwing on fasteners. Although the impact wrench can screw on fixings successfully, using an impact wrench for this sort of work risks over-tightening the fastener, stripping it or even breaking it if one is not careful, due to the relative uncontrolled application of the high amounts of torque from the impact wrench. This is even more important to consider for fasteners that need to be set to specific torque levels like those on vehicle wheels where a torque wrench is required.
What to look for in an Electric Impact Wrench
Corded vs Cordless
As alluded to above, electric impact wrenches can be either mains-powered (corded) or battery-powered (cordless) and this represents one of the first major decisions one must make when looking to buy one for the home workshop. Some of the decision will be based on personal preference, but one should also consider where the tool is going to be used especially with regards to access to mains power. In general, corded impact wrenches are the domain of the less reputable brands of power tool retailer but they also tend to provide more power at a lower price point. More reputable name-brand power tool manufacturers, better known for selling higher quality power tools, tend to focus almost exclusively on the cordless battery-run impact wrenches.
For mains-powered electric impact wrenches, the power input level is measured in Watts (W). In general, higher wattage means a greater maximum torque the machine can produce, so for corded impact wrenches one wants to lean towards the highest powered machine that is affordable. In the case of battery-operated impact wrenches, power is delineated in voltage (V) and generally speaking, the higher the voltage, the higher the power the tool can output. Battery-operated impact wrenches come in a small set of discrete voltages usually as 12V, 18V, 24V or sometimes 36V which is usually dependent on the size of the power tool. In the case of the 1/2” electric impact wrench common with DIYers, batteries are typically the 18V (or sometimes 20V) variety.
Somewhat correlated with the power at which the electric impact wrench operates, one of the key specifications to look at when choosing an electric impact wrench is the maximum torque that it can deliver (sometimes referred to as the maximum fastening torque). This is defined by the highest peak torque delivered by the impact wrench when locked into a perfectly solid object. Obviously choosing an electric impact wrench with the highest maximum torque that is within one’s budget should be the key driver here. However, another type of torque metric called the “nut-busting” maximum torque is also sometimes provided by manufacturers which can lead to some confusion. As its name suggests nut-busting torque is defined by as the ability of the impact wrench to loosen a nut with the specified amount of torque in some specified time period. Since the ‘specified time period’ of the nut-busting torque metric just introduces another variable which may be different from manufacturer to manufacturer, the nut-busting specification may not be as useful when comparing between impact wrenches, with the earlier described maximum torque specification being the better metric for comparisons.
No-Load Speed (rpm)
The no-load speed refers to the number of revolutions per minute (rpm) at which the motor spindle in the impact wrench turns. In simple terms, the faster the spindle turns, the higher the force at which the ‘hammer’ will strike a stuck fastener. Therefore, by controlling the no-load speed, impact wrenches can have variable maximal torques. In practice, this comes in the form of different gear settings on the impact wrench, which can provide a small set of discrete maximal torques from the machine.
The impacts-per-minute of an impact wrench refers to the rate at which the hammering action of the machine is delivered. Intuitively, one can deduce that the higher the rate, the more often the peak torque is applied to the nut being loosened and should result in a faster end result. In reality, however, the rates of any impact wrench are all sufficiently high that differences in the speed of the ‘nut-busting’ action will likely be minimal. So unless the impact wrench is needed for some highly competitive event, such as NASCAR or Formula One racing, the impacts-per-minute metric will be mostly irrelevant to the regular user.
Impact wrenches tend to be relatively heavy power tools for their overall size, with the additional working parts in electric versions making them even heavier. As a consequence, weight is an important metric to take into account when purchasing an impact wrench especially if the tool is to be used over long stretches of time. In the case of some cordless battery-operated impact wrenches, particularly from the more established power tool companies, a range of different capacity batteries are often compatible with the impact wrench. Consequently, the overall weight of the battery-powered tool can vary depending on the size of the battery installed.
Impact wrenches are inherently noisy machines, especially compared to other power tools, with ratings generally above the 100 dB level. This means that ear protection should be used especially when using the impact wrench over long periods of time or on a regular basis.
Impact wrenches are generally quite bulky tools that can be vulnerable to damage if not cared for. One accessory that is always highly recommended for such tools is a carry case to protect it during storage and transportation. Carry cases for the impact wrench usually come in one of two forms, a soft material bag-type case or a hard plastic case, with the latter type generally being the more favoured for its greater robustness.
Popular 1/2-inch Electric Impact Wrenches in the UK
(Watts or Volts)
(Watts or Volts)
* Weight includes battery pack (if battery-powered)
** The use of different battery pack sizes changes the overall weight of the impact wrench
Electric Impact Wrench Reviews
Ryobi R18IW3 Impact Wrench Review
The R18IW3 from Ryobi is an impact wrench ideally suited for the occasional job typically encountered by DIYers, such as the undoing of car wheel nuts, or other stubborn nut or bolt-releasing tasks. It is not, however, designed for working on the wheels of larger commercial vehicles nor for the daily heavy use of professionals. The Ryobi R18IW3 power wrench also cannot match the power of battery-powered premium brands such as those from DeWalt and Snap-on, but since it is only a fraction of the price of these premium machines still makes it excellent value for money. As expected from a battery-powered device, the R18IW3 is also no match when pitted against mains-powered impact wrenches and certainly not against air-powered ones. Both tethered tool types can provide high levels of torque for almost unlimited amounts of time from their essentially endless power supplies, be-it electricity or compressed air. However, the R18IW3 comes with all the obvious advantages of being cordless.
The R18IW3 impact wrench uses a brushed electric motor, which can be set to rotate at three different speeds, generating up to 3200 impacts per minute and providing three different torque output settings, the maximum of which is 400Nm. The highest torque setting is useful for removing stubborn nuts or bolts, while the lower setting can then be used for spinning the fixings out. The lower and medium torque ranges are also useful for the undoing of smaller stuck bolts where the risk of them shearing off is higher when using too high a torque level. The lower torque levels are also useful for the initial screwing on of fixings, before being hand tightened to the required torque level with a more accurate torque stick. The Ryobi impact wrench also has a variable speed trigger which provides more refined control over the torque outputs. It should be noted, however, as this is a brushed-motor device, that the first few runs of the Ryobi machine may give off a slight burning odour. This is normal and typical of tools with brushed motors as the new brushes are worn in.
The Ryobi impact wrench uses an 18V battery belonging to Ryobi's universal battery system, known as ONE+, which is used across a range of power tools from the company The R18IW3 can be bought with or without a battery. The latter situation provides excellent value for money if the owner already has a high capacity Ryobi battery from another ONE+ battery-powered tool. In our opinion, however, it is not recommended to buy this impact wrench with the 2 Ah battery included, since one of the primary reasons for earlier poor reviews of the R18IW3 is likely due to the use of lower capacity batteries which provide a lower level of function. Therefore, it is highly recommended to use the R18IW3 impact wrench only with the higher 4 or 5 Ah batteries to get the most out of the tool. Although any Ryobi battery capacity should provide the same power output, the higher capacity ones can maintain peak power for longer periods. This is especially important for an impact wrench, which is primarily designed to loosen stubborn or rusted-on nuts or bolts through the continuous application of peak power, usually where more conventional methods have failed. The same applies to using fully-charged batteries on stubborn fixings which will ensure that the R18IW3 can maintain its peak torque level for as long as possible.
Like almost all impact wrenches, the R18IW3 sports a 1/2” (12.7 mm) square anvil with a locking pin that holds the socket securely but also allows for the quick changing between different-sized bits. Adjacent to the drive are three LED lights that do an excellent job of lighting up the work area when the impact wrench is in use. The R18IW3 is of medium weight and, depending on the capacity of the Ryobi ONE+ battery fitted, will range from 2 kg, for the smallest 1.3 Ah battery installed, to 2.8 kg when coupled with the biggest 5 Ah one.
A couple of other stand-out features of the Ryobi R18IW3 impact wrench are found in its overall size and the accessories that accompany it. Firstly, the R18IW3 is a relatively small device compared to its peers, making it particularly useful when working within tight spaces. Accessories-wise, the R18IW3 comes with a carry case in the form of a soft bag, which is useful for storage and transportation of the tool, although we would have preferred a hard case for better protection. The impact wrench also comes with an adaptor that can transform the square drive into a hexagonal receptacle for accepting screw-driving impact bits. This, together with the ability to set the machine at lower torque levels typical of screw-driving, transforms the Ryobi impact wrench into an impact driver, obviating the need to purchase a separate machine to drive in or undo stubborn screws.
Noise-wise, the R18IW3 is one of the noisiest electrically-powered impact wrenches on the market, with ear protection recommended if using it for an extended session. As for all impact wrenches, remember to use the Ryobi tool only with sockets designed for impact wrenches, since these can better transfer the power of the device to stubborn fixings without the risk of the sockets getting damaged in the process.
Overall, the Ryobi R18IW3 impact wrench is a good buy for the DIYer who needs to use an impact wrench occasionally on smaller vehicles and smaller jobs. It is not really designed for larger, more difficult loosening tasks nor for professional use where it will likely be found to be lacking in power and longevity. The R18IW3 is particularly good value for money if bought without a battery, otherwise having to buy a suitable battery will bring down the overall value one gets from the tool significantly. It also should not be forgotten that battery-powered impact wrenches are inherently weaker than their mains-powered or air-powered brethren, and expectations from the Ryobi power tool should be managed accordingly. Indeed, most cordless impact wrenches will fail to loosen very heavily torqued fittings where tethered devices will often succeed.
Makita DTW1002Z Impact Wrench Review
As one of the most powerful electric impact wrenches on the market, the Makita DTW1002Z is designed to tackle some of the most challenging of nut-busting jobs. This Makita impact wrench can produce a peak unfastening torque of 1600 Nm and a maximum impact rate of 2200 ipm which together make it capable of undoing even the most intractable of fixings. The high power of the Makita impact wrench also allows it to tackle nut and bolt fixings up to a generous M30 in size (high tensile bolt sizes of up to M24), all via a medium-sized 1/2” (12.7 mm) anvil.
In addition to its unfastening abilities, the Makita DTW1002Z impact wrench also has a maximum fastening torque of 1000 Nm, along with three settable power levels and a variable speed trigger to help reduce fault tightening, which allows it to be used to screw on stubborn fixings as well. However, tightening fixings to an accurate torque level is always difficult with any impact wrench, and generally not recommended. A bespoke torque wrench is the go-to tool to use in such situations but the initial screwing-on of the nut or bolt can be performed with a power wrench such as the Makita DTW1002Z.
In addition to exceptional power, the Makita impact wrench also has some other features that help categorise it as one of the premium power tools. These include a high build quality (typical of Makita tools in general), a brushless motor, which eliminates the need for carbon brushes giving it a longer lifespan, and an electric brake to stop the impact wrench quickly on trigger release.
The Makita DTW1002Z is powered by an 18V Lithium-ion battery that belongs to Makita’s universal battery system where batteries can be swapped between a range of power tools from the company. As a result, different capacity batteries can be used with the Makita impact wrench providing it with various maximum run times. Generally speaking, however, battery capacities of 3, 4 and 5 Amp-hours are best suited for the power requirements of this Makita power tool. The battery itself attaches to a less rigid point on the handle of the Makita impact wrench which dampens down excessive vibrations generated by the powerful machine thereby protecting the battery. However, this flexibility is often misinterpreted by inexperienced operators as a build flaw in the power wrench.
With so much power at one's fingertips, it is only natural that the impact wrench will also be one of the heaviest on the market with a weight of between 3.3 and 3.6 kg depending on the battery capacity used. This can make using the DTW1002Z for long periods tiring. In addition, the Makita DTW1002Z is also one of the biggest and bulkiest in its power tool category making it more difficult to handle especially in tight spaces. Therefore, when buying the Makita DTW1002Z, it is also recommended to invest in impact-rated extensions and swivel joints in order to make full use of the impact wrench. As for poorly-lit environments, such as the aforementioned tight spaces, the Makita impact wrench sports twin LED job lights which can be useful when working in darker areas.
Accessories-wise, for such a heavy and bulky machine, it is perhaps a little surprising that the Makita impact wrench does not come with its own carry case. However, this is mainly due to the DTW1002Z being compatible with Makita’s universal toolbox system which is designed to accommodate a range of power tools simply by using a tool-specific case inlay. The Makita DTW1002Z-specific inlay (model number, 837645-9, shown below) and a compatible Makita plastic carry case (MakPac Type 3 connector case, model number 821551-8) are both sold separately. The Makita DTW1002Z impact wrench does not come with any impact sockets either, so these too will have to be procured separately. As for all impact wrenches, but especially so with this Makita machine, it is important to procure impact-rated sockets as this Makita machine will easily split regular ones.
As for negatives with the Makita DTW1002Z impact wrench, there is not much to say here other than the attachment mechanism that holds impact sockets to the square drive of the power tool could do with a bit of design upgrade. The current hog-ring type design for the anvil friction ring is not optimal as any sockets that are attached, particularly heavy ones, can too easily fall off the power tool.
Overall, the Makita DTW1002Z is one of the biggest and most powerful cordless 1/2” electric impact wrenches that the Japanese company makes. Indeed, even amongst its premium brand competitors, the Makita impact wrench outperforms, beating equivalent machines from the likes of DeWalt and Milwaukee in terms of sheer nut-busting power. As a result, the Makita impact wrench is the go-to tool when other impact wrenches have failed to undo a stuck fixing. In fact, the machine is so powerful that one needs to take care not to snap stuck nuts and bolts, or if the impact wrench is used to tighten fixings. Thankfully, the variable power levels that are on the machine reduce the chances of that happening, with the vast majority of jobs only requiring the lowest power setting. As one might expect from such a capable and premium tool, the cost of the machine is relatively high, especially when compared to more economical brands, but that is the price that one should expect to pay if an impact wrench that is essentially unbeatable is called for.