Cordless screwdriver buying guide

Before you set about choosing your power screwdriver ask yourself the following questions and consult the table below. To make a more informed choice and to find the perfect tool to match your DIY skills, go ahead and check out the chapters of this guide.

1. What type of screw driving tasks do you want to carry out? It goes without saying that inserting screws into decking boards requires more turning force than assembling flatpack furniture. The higher the torque provided (in newton metres or Nm), the greater the screw driving force. Similarly, the size and weight of the tool determines how easy it is to handle.

2. How often do you plan to use the tool? Your choice of brand and price range will depend largely on whether you plan to use the tool every day of the week or just a handful of times a year. Always choose a high-quality brand for regular use and look to professional trade ranges for heavy-duty use.

3. Do you need to drill holes and into which types of materials? You'll need more power – or even a different tool – to drill through 12mm concrete than you will to get through 6mm plasterboard. In other words, if you plan to drill through hard materials, you might need to look for a combi drill which can offer hammer action and a higher voltage rating. Depending on your needs, you might find yourself needing two tools including one corded drill for regular drilling.

4. How long do you need to use the tool for? The battery duration of cordless screwdrivers is measured in ampere hours (Ah); the higher the Ah rating, the longer the battery will last (though this does also depend on application). For longer tasks, it's a good idea to get two batteries so you can switch over as you work.

Cordless screwdriver, impact driver or combi drill: which is right for me?

1 + 2 = information for guideline purposes only. Values vary widely depending on the power tool.

It's important to note that terms can vary depending on the manufacturer. A cordless screwdriver might also be called a power screwdriver or electric screwdriver. The terms drill driver, impact driver, combi drill and even cordless drill also often get muddled up. Bear in mind that a cordless screwdriver will always be smaller, more compact and offer lower torque levels than a drill driver or impact driver. From a purely technical point of view, an impact driver is primarily designed for screw driving and not for drilling, even if most can just about manage to drill through wood or metal. In terms of performance, these tools sit somewhere between a cordless screwdriver and combi drill.

Most DIYers will struggle to see the difference between a cordless screwdriver, drill driver, impact driver, and a battery-powered combi drill. A drill driver can be seen as a cordless drill with the option to drive screws.

It's worth noting that regular drills, corded and air drills, can also be used to insert or loosen screws, but these tools work best for drilling. A combi drill, on the other hand, is designed for screw driving as well as drilling. These tools provide hammer action meaning they can screw into masonry and other hard materials. However, they are not terribly practical or accurate when screw driving in softer materials and are not recommended for any task that demands precision.

It's worth mentioning that cordless screwdrivers, impact drivers and combi drills all feature a reverse switch for loosening screws.

Impact wrenches

Impact wrenches are electric or air-powered tools designed exclusively for high torque applications in mechanics. Picking the right impact wrench primarily comes down to determining the kind of torque level and impact rate (in blows per minute) you require. These tools require special bits and sockets.

Drywall screwdriver

Drywall screwdrivers are specially designed for driving screws into plasterboard. These tools may be collated for automatic screw firing. When choosing a drywall screwdriver, you need to think about power, RPM and whether or not you need a collated tool.

As explained above, the terms cordless screwdriver, drill driver and impact driver often get mixed up. Generally speaking, cordless screwdrivers will always be smaller and come in all price ranges, while impact drivers will usually come from semi pro and trade brands.

To avoid any confusion and to help you pick the right product, remember the following:

• a cordless screwdriver can be straight or pistol-shaped in design and will usually offer a maximum of 10 Nm which is enough to assemble flat-pack furniture and work on electrical equipment, household appliances and small hardware ;

• a drill driver is a pistol-shaped tool which can provide about 40 Nm for drilling and inserting screws into household appliances, wood, and so on. An impact driver, on the other hand, is designed primarily for screw driving and offers higher torque for tasks like building decking.

Please note: you will occasionally find a cordless screwdriver rated 7.2 V and these tools can deliver up to 15 Nm.

Impact driver

Impact drivers are mainly used by kitchen fitters, joiners and anyone who assembles flatpack furniture on a very regular basis. These tools are able to drill holes if fitted with special bits but are not generally purchased for this purpose. Impact drivers aren't equipped with a chuck but rather a 1/4'' hex shank bit holder.

Combi drills

Combi drills are more versatile but also heavier than other tools making them trickier to handle. This makes them less well suited to precision screw driving tasks or working in tight spaces. These tools are designed to drill as well as they drive screws, and are usually bought to perform both tasks. Combi drills are fitted with 10 or 13mm keyless chucks where drill bits and bit holders can be inserted. These tools can even drill through concrete on hammer mode.

Electric screwdrivers are used for precision screw driving and low torque tightening for tasks like assembling flatpack furniture. Weighing in at 450 g on average, cordless screwdrivers are lightweight, compact and very easy to handle. They usually come with a built-in battery for ease of use.

These tools can be pistol-shaped or straight. They may even feature a right angle head for working in tight corners. Cordless screwdrivers can be equipped with a time-saving quick release chuck which works like a magnetic bit holder. The RPM of these tools dictates, in part, how quickly it can tackle screws. Bear in mind that cordless screwdrivers cannot be used for high torque applications as they are limited to about 10 Nm. If you are looking for any more than this, go for a drill driver, impact driver or combi drill.

Features of a cordless screwdriver

• 3.6 V to 7.2 V

• 1 Ah to 2 Ah

• Li-Ion battery

• 200 to 600 RPM

• 2 to 10 Nm

• Ø7mm max. screw capacity

Impact drivers are designed specifically for screw driving tasks. They offer better performance than cordless screwdrivers and drill drivers, but are less powerful than combi drills. These power tools are designed for regular or heavy-duty use and are typically used by tradespeople.

Weighing in at about 1.1 kg on average, an impact driver doesn't feature a traditional chuck. Instead it has a quarter-inch hex shank collet. These pistol grip tools usually feature a removable battery and can be fitted with a right angle attachment.

While drill drivers are able to both drill and drive screws with relative ease, impact drivers have limited drilling capacity. That said, they can be fitted with hex shank drill bits and will just about manage to drill through wood and metal. The RPM of these tools dictates, in part, how quickly they can tackle screws.

Features of an impact driver

• 10 V to 18 V

• 1 to 4 Ah

• Li-Ion battery

• Max. no load speed of 2500 RPM

• 100 to 200 Nm

• Torque settings

• Ø30 mm drilling in wood

• Ø10 mm in metal

• Ø7mm max. screw capacity

Combi drills are designed to both drill and drive screws, and offer better drilling performance than impact drivers. Technically, a combi drill can be corded or cordless. In reality, combi drills are usually battery-powered tools. They are a popular choice with DIYers thanks to their ability to both drill and drive screws.

Bulkier and trickier to handle, combi drills are often wrongly referred to as hammer drills thanks to the hammer action they provide. They work well for hard materials and masonry, but are not ideal for any screw driving task that requires precision.

Unlike impact drivers, combi drills feature a chuck which is used to hold screwdriver bits or other accessories like hole saws , paint mixer attachments or drill pumps.

These tools usually come with a removable battery. Performance and features will vary depending on the model, but these tools usually weigh between 1.5 and 3 kg. Screwing speed and drilling capacity will, in part, be determined by the tool's RPM.

Features of a combi drill

• 12 V, 14.4 V, 18 V or 36 V

• 5 Ah to 6 Ah

• Ni-cd or Li-Ion battery

• 200 to 3000 RPM

• 20 Nm to 135 Nm

• Ø102 mm drilling in wood

• Ø 16 mm drilling in metal

• Ø20 mm drilling in masonry

• Ø12 mm max. screw driving

• 25,000 blows per minute in hammer mode (optional)

• Keyless 10 or 13mm chuck

• Torque settings

• Variable speed

• Ni-cd or Li-Ion battery

Additional features and accessories

• Tool belt hook

• Extra handle

• In-built bit holder

• Interchangeable chuck (SDS, angled bit holder, short chuck with 1/4 inch collet)

• Built-in LED light for improved visibility

• Soft grip handle for easy grip

• Plastic case

Voltage

The power of a cordless screwdriver, impact driver or combi drill is measured in volts (V). The voltage of a power tool determines how much power your tool battery can provide. The higher the voltage, the more powerful the tool.

Ampere hours

The ampere hour (Ah) rating of a power tool battery describes the number of amps available within one hour and determines how long the battery can last between charges. The higher the Ah rating, the longer you can use your power screwdriver. As an example, a 3 Ah battery will provide 3 amps (A) for an hour or 1A for three hours.

The components of a battery determine its characteristics. Two types of batteries are used for combi drills: Ni-cd and Li-Ion. Comparatively, impact drivers and cordless screwdrivers will only usually come with Li-Ion batteries as nickel cadmium (Ni-cd) batteries are much heavier and bulkier making them unsuitable for compact, lightweight tools.

Features of a nickel cadmium (Ni-cd) battery

• Inexpensive.

• Heavy and bulky.

• Memory effect (must always be charged to 100%).

• Slower to charge.

• Loses power as it discharges.

Features of a Lithium-Ion (Li-Ion) battery

• More expensive.

• No memory effect.

• Quicker to charge.

• Battery level indicator.

• No power loss when discharging; maintains power until battery runs out.

• Optional CoolPack system for better heat management and longer run times.

• ECP (Electronic Cell Protection) system to protect the battery from overloading, overheating and deep discharge.

Please note: it's always a good idea to get a power tool with two batteries so you can switch over as you work (one can charge while the other is in use). It's also important to look at the charging time of a battery.

Torque is measured in Newton Metres (Nm) and determines the turning force for screw driving or drilling. The higher the torque level, the more turning force the tool can apply.

Cordless screwdrivers can produce a maximum 10 Nm, drill drivers can apply up to 40 Nm while an impact driver can deliver up to 150 Nm.

In comparison, a mid-range combi drill will provide a torque level of about 55 Nm which is enough to cover the needs of most DIYers.

Choosing the right torque level for your fasteners

No matter which type of motor you choose, it will contain a stator and rotor. The rotor is the rotating part and the stator is the stationary component. The stator is a cylinder that features evenly spaced coils. The space between the rotor and the stator is called the air gap. Both brushed and brushless motors work through electromagnetism.

Brushless motors

A brushless motor is synchronous and is not fitted with a carbon brush. Specifically, this means that these motors heat up less during use, last longer and offer better performance than brushed motors as the rotational speed is proportional to the voltage applied. Most high-end power tools – and even some mid-range tools – feature brushless motors.

Brushed motors

A brushed motor is asynchronous and features a carbon brush. Brushed motors are the original type of motor and the carbon brushes themselves are wear pieces. These motors are less efficient as the rotational speed is asynchronous meaning it is not proportional to the voltage applied. This means the motor heats up more easily and there is a greater difference between the input and output power (power losses due to carbon brush friction). Brushed motors are used for low-end tools and some mid-range tools.

Screwdriver bit type

The screwdriver bit needs to match the drive of your screw. Here are the most common screwdriver bits:

• pozidriv (PZ);

• crosshead or phillips (PH);

• flathead or slotted;

• torx (T);

• resistorx ou tampertox (TT);

• hex or allen key;

• drive type:

• size (measured differently depending on type);

• material: primarily steel, titanium or diamond coating.

Screwdriver bits: the basics

Maintaining a power screwdriver

Whether you go for an electric screwdriver, a drill driver, an impact driver or a combi drill, the only maintenance required involves replacing the carbon brush (if you choose a tool with a brushed motor). Carbon brushes are inexpensive, easy to fit and won't need to be changed often.

The chucks of low-end tools can lose torque over time but can be purchased separately and are easy to replace. Power tool batteries may also become less efficient in terms of power and battery life. Depending on your tool and whether or not you choose a removable battery, you can either replace the battery or have it reconditioned which involves replacing the components. It's worth noting that, depending on how much your tool cost, it can be less expensive to replace the tool itself as batteries can be expensive.

Cordless screwdriver warranties

Warranties generally stretch two to three years depending on the manufacturer. If you are replacing a tool, be sure to take your old tool to a recycling centre.

More information on drilling

• Drill buying guide

• How to drill into walls

• How to drill through glass

• How to drill through tile

• Drill bits buying guide

• Screwdriver bit buying guide

• Wall plug buying guide

• Power tool battery buying guide

• Power tool battery charger buying guide

• Impact wrench buying guide

• Pillar drill buying guide

• Rotary hammer buying guide

• Drill accessories buying guide

• Drywall screwdriver buying guide

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