What is an Impact Driver

An impact driver is a powerful, compact power tool designed to drive screws and fasteners into tough materials with greater force than a standard drill or screwdriver. Unlike a conventional drill driver, which applies continuous torque, an impact driver delivers high torque in short, rapid bursts using a combination of rotational force and concussive blows. This makes it particularly effective for driving long screws, lag bolts and other heavy-duty fixings into dense materials such as hardwood, brick or metal.

Impact drivers are widely used in construction, carpentry, joinery, roofing and general building maintenance across the UK. They have become essential on job sites for tasks that require both speed and torque, offering improved performance and reduced user fatigue compared to manual or lower-powered alternatives. With the growth of cordless tool platforms and lithium-ion battery technology, impact drivers are now more accessible and versatile than ever.

Where Impact Drivers Are Commonly Used

Impact drivers are commonly found on construction sites, particularly during first and second fix stages. They are ideal for fitting timber frames, securing flooring sheets, assembling decking, erecting stud walls and installing door hardware. Joiners use them for cabinet assembly and fixing into hardwoods, while roofers favour them for driving coach bolts and long fixings into structural timbers.

In metalworking, impact drivers can be used for fixing cladding or driving self-tapping screws into steel framing. Electricians and plumbers may also use impact drivers when mounting heavy fixtures or brackets, especially in environments where standard drills struggle to cope.

While they are not typically used for drilling holes, some impact drivers can accommodate hex-shank drill bits for light-duty drilling in softer materials. However, their real strength lies in fastening applications, especially where traditional drills might stall, overheat or strip screw heads.

How Impact Drivers Work

The key difference between an impact driver and a regular drill lies in the internal mechanism. When resistance is detected, the tool automatically engages a spring-loaded hammer and anvil system that delivers rotational impacts. These percussive bursts create sudden increases in torque that help twist stubborn fasteners without transferring excessive force to the user’s wrist or arm.

This makes impact drivers incredibly efficient at driving screws without the need for pre-drilling or excessive downward pressure. Because the impacts are rotational rather than linear, the tool does not vibrate like a hammer drill and is more comfortable to use over extended periods.

Most impact drivers use a ¼ inch hex chuck rather than a traditional three-jaw chuck. This quick-release mechanism allows for fast bit changes and is compatible with hex-shank screwdriver bits, nut drivers and some drill bits. Modern cordless models typically run on 12V, 18V or 20V platforms, with brushless motors providing greater efficiency, runtime and durability.

Advantages and Disadvantages of Impact Drivers

One of the biggest advantages of an impact driver is its torque output. It can drive long screws or bolts into tough materials with ease, reducing the need for pilot holes or over-tightening. The concussive action also minimises the risk of cam-out, where the screwdriver bit slips out of the screw head, damaging both the bit and the fixing.

Impact drivers are compact and lightweight, making them ideal for working in tight spaces or overhead. Their ergonomic design and reduced kickback improve user safety and comfort, especially on repetitive tasks.

However, impact drivers are not without limitations. They are generally not suitable for precision work, as their high torque can easily overdrive or snap smaller screws. They are also much louder than drills, and prolonged use in enclosed spaces may require ear protection. Unlike combi drills, impact drivers do not have a clutch or adjustable torque settings, so control relies on user technique and trigger sensitivity.

Another consideration is bit compatibility. Because of the high torque and percussive force, standard screwdriver bits can wear out quickly or break. It is important to use impact-rated accessories that are designed to withstand the additional stress.

Impact Driver vs Drill Driver

A common question among tradespeople and DIYers is whether to use an impact driver or a drill driver. While both tools can drive screws, their functions are not identical. Drill drivers offer greater control, adjustable torque settings and the ability to drill clean holes in timber, plastic and masonry when paired with the correct bits. They are better suited to fine joinery, cabinet work and general-purpose tasks.

Impact drivers, on the other hand, are built for speed and strength. They excel at repetitive or heavy-duty fastening tasks, especially where drills would stall or fail. On site, many tradespeople carry both tools and switch between them depending on the application. Some manufacturers offer combination kits containing both an impact driver and a drill driver as part of a cordless system.

Cost, Brands and Practical Considerations

The cost of an impact driver varies depending on brand, voltage, features and whether it is sold as a bare unit or part of a kit with batteries and charger. Entry-level models start around £60, while professional-grade tools from brands like DeWalt, Makita, Milwaukee or Bosch can cost £150 or more. Brushless motors, variable speed settings and compact housings are common in mid to high-end models.

When choosing an impact driver, users should consider battery platform compatibility with other cordless tools, the availability of impact-rated accessories and the types of fasteners they use most often. For site use, a robust carry case and spare batteries are also worth considering.

Safety and Maintenance

Although impact drivers are safer to handle than high-torque drills, users must still observe basic safety precautions. This includes wearing eye and ear protection, checking that bits are securely inserted and ensuring the tool is not used for drilling masonry or tiles, which could cause failure or injury.

Maintenance is straightforward. Keeping the tool clean, avoiding overloading, and using the correct bits will extend its lifespan. For professional use, regular inspection of the chuck and brushes or brushless motor is advisable, especially if the tool is used daily.

Common Misconceptions About Impact Drivers

One common misconception is that impact drivers can replace all drilling tasks. While they are highly effective for driving fixings, they are not designed for precision drilling or use with round-shank drill bits. Another misunderstanding is that more power always means better performance. In reality, too much torque can strip threads, snap screws or damage delicate materials.

Some users also mistakenly believe that impact drivers are only for trade professionals. In fact, many serious DIYers find impact drivers extremely useful, especially when assembling timber frameworks, fencing or flat-pack furniture. Provided the correct accessories are used, impact drivers can be a time-saving and reliable addition to any tool kit.

Conclusion

An impact driver is a powerful and compact fastening tool designed for high-torque applications in construction, joinery and general building work. It works by delivering rapid rotational impacts that make it highly effective for driving screws and bolts into tough materials. While not a replacement for a drill, it excels in speed, power and control for repetitive or heavy-duty fixing tasks. With the right accessories and technique, an impact driver can significantly boost productivity and reduce fatigue across a wide range of jobs.