Topic
Impact drivers
An impact driver turns a 1/4 inch hex bit with rotational blows, so long screws and coach bolts go in without wrist strain. It drives; it is not a drill for masonry.
- Bit holder
- 1/4 in hex (6.35 mm)
- Typical torque
- 150 to 200+ Nm
When the screw resists, a spring and hammer inside the driver deliver rotational blows around the axis, many times a second. That is why an impact driver sinks 100 mm decking and timber screws that would stall a drill.
The 1/4 inch hex chuck takes impact-rated bits and hex shank drill bits only. Use bits marked impact or torsion: standard bits snap under the blows.
Many drivers have speed or torque modes. A low mode is kinder to small screws and hinges; there is no clutch, so a combi drill still wins for delicate work and for anything that needs a round shank bit.
Common mistakes
- Expecting an impact driver to drill brick: its blows turn the bit, they do not push it into masonry.
- Using non-impact bits, which shatter or round off quickly.
Guides on this topic
- What is an impact driver used for?How an impact driver's rotational impacts and hex bit holder work, and the jobs from decking screws to coach bolts where it beats a drill.Guide
- Impact driver vs impact wrench: hex bits or square drive?Hex bit holder against square anvil, typical torque ranges and why wheel nuts and large bolts usually call for an impact wrench, not a driver.Comparison
- Impact driver vs cordless screwdriverSmall cordless screwdrivers suit flat-pack and electrics; impact drivers sink long screws and coach bolts. Compare torque, size and when to use a drill instead.Comparison
- Impact driver torque settings and speed modes explainedWhy impact drivers have speed modes not a clutch, what the Nm figure means, and how to use modes for self drilling screws, small screws and bolts.Guide
- Impact driver bits: what makes them impact ratedHex shank sizes, torsion zones, PZ, PH and Torx tips for UK screws, and hex shank drill bits for impact drivers, explained simply.Guide
- How to use an impact driverHow to use an impact driver safely and well: loading hex bits, speed modes, pilot holes, avoiding stripped heads and snapped screws in timber and metal.How-to
- Can an impact driver remove wheel nuts?Typical wheel nut torque against impact driver output, hex to socket adaptors, and why a torque wrench should always finish the job.Guide