Impact Wrenches

About Impact Wrenches

Impact wrenches are powerful, high-torque tools designed to make light work of tightening and loosening nuts and bolts that would otherwise require considerable effort with manual tools. Unlike impact drivers which use hexagonal bit holders, impact wrenches feature square drive fittings (typically ¼", ?", ½" or ¾") that accept socket sets, making them indispensable for automotive work, construction, and heavy machinery maintenance. The rotational impact mechanism delivers rapid bursts of torque, allowing these compact tools to generate far greater turning force than their size would suggest.

Tooled-Up.com stocks impact wrenches in various configurations to suit different applications and budgets. Cordless models powered by lithium-ion batteries offer maximum portability and are available in voltages ranging from compact 12v units for lighter duties through to powerful 18v professional-grade tools capable of delivering over 1,000Nm of torque. Corded electric impact wrenches provide continuous power for extended use, available in both 240v for standard workshop environments and 110v for building site applications with transformers. For those requiring pneumatic options, a comprehensive selection of air impact wrenches can be found in the dedicated Air Tools section.

Professional brands featured at Tooled-Up include Makita, DeWalt, Bosch Professional, Milwaukee, and Draper, each offering distinct advantages in terms of power delivery, battery compatibility, and durability. Whether you're a mobile mechanic requiring cordless convenience, a workshop technician needing consistent mains power, or a construction professional working with heavy structural fixings, there's an impact wrench designed to meet your specific requirements.

Jargon Buster

• Square Drive Size: The measurement (in inches) of the square anvil that accepts sockets – common sizes include ¼", ?", ½" and ¾". Larger drives accommodate bigger sockets and handle higher torque applications.
• Torque (Nm): Newton metres – the measurement of rotational force the tool can deliver. Higher Nm ratings indicate greater fastening and loosening capability, with professional models ranging from 100Nm to over 1,600Nm.
• Brushless Motor: Modern motor technology that eliminates carbon brushes, resulting in greater efficiency, longer runtime, reduced maintenance, and extended tool lifespan compared to brushed motors.
• Impact Rate (IPM): Impacts per minute – indicates how many times per minute the tool delivers its rotational hammering action. Higher IPM typically means faster work completion.
• No-Load Speed (RPM): Revolutions per minute when the tool isn't under load. This measurement helps determine how quickly the tool can run down or tighten fasteners before encountering significant resistance.
• Impact-Rated Sockets: Specially hardened sockets with a distinctive black finish, designed to withstand the repetitive shock loads generated by impact wrenches without cracking or shattering.

Who Uses Impact Wrenches?

Impact wrenches serve professionals and enthusiasts across numerous trades and industries:

• Motor Mechanics and Auto Electricians: Removing and fitting wheel nuts, suspension components, engine mounts, and exhaust systems
• HGV and Plant Mechanics: Servicing heavy vehicles, agricultural machinery, and construction equipment with larger fasteners
• Scaffolders: Assembling and dismantling scaffolding structures with speed and torque control
• Steel Erectors and Structural Engineers: Fastening structural bolts on construction sites and fabrication workshops
• Mobile Tyre Fitters: Rapid wheel changes in roadside assistance and fleet maintenance
• Plant and Machinery Maintenance Engineers: Servicing industrial equipment, conveyors, and production machinery
• Agricultural Engineers: Maintaining tractors, harvesters, and farm equipment in field and workshop settings
• DIY Enthusiasts and Home Mechanics: Vehicle maintenance, garden machinery repairs, and general fastening tasks
• Fabricators and Welders: Assembly work requiring repeated fastening of bolted connections

How to Choose the Right Impact Wrenches

Power Source: Cordless models offer portability and convenience for mobile work, site applications, and locations without mains power. Battery-powered tools in the 18v class provide an excellent balance of power and runtime for most professional applications. Corded 240v models deliver consistent power for workshop use and extended sessions without battery management concerns, whilst 110v versions suit building sites with transformer systems.

Torque Requirements: Match the tool's maximum torque output to your typical applications. Light automotive work and general assembly may only require 200-400Nm, whilst wheel changes demand 400-700Nm, and heavy structural work or larger vehicles need 1,000Nm or more. Remember that manufacturers' specifications represent maximum capability – real-world performance may vary.

Drive Size Selection: Choose according to the socket sizes you'll use most frequently. Compact ¼" and ?" drives suit smaller fasteners and confined spaces, ½" drives handle most automotive and general engineering work, whilst ¾" drives are reserved for heavy industrial applications and large fasteners.

Weight and Ergonomics: Consider the tool's weight, particularly for overhead work or extended use. Compact models starting around 1-1.5kg reduce operator fatigue, whilst heavier high-torque units may weigh 2-3kg or more. Rubberised grips and well-balanced designs improve comfort during prolonged use.

Speed and Torque Control: Variable speed triggers and multiple torque settings provide greater control for different fastener sizes and materials. Some advanced models offer programmable modes for specific applications, preventing over-tightening of critical fixings.

Battery Compatibility: If you already use a particular cordless platform, choosing an impact wrench compatible with your existing batteries maximises value and convenience. Consider amp-hour ratings – higher Ah batteries provide longer runtime but add weight.

Popular Accessories

• Impact Socket Sets: Black-finished impact-rated sockets in metric and imperial sizes, available in individual pieces or complete sets
• Socket Adaptors and Extensions: Impact-rated extensions for reaching recessed fasteners, wobble extensions for angled access, and drive adaptors
• Wheel Nut Sockets: Thin-wall impact sockets specifically designed for vehicle wheel nuts, often including common sizes like 17mm, 19mm, and 21mm
• Universal Joints: Impact-rated swivel joints allowing access to fasteners at awkward angles
• Protective Rubber Socket Covers: Prevent damage to alloy wheels and finished surfaces during wheel changes
• Replacement Batteries and Chargers: Spare battery packs and rapid chargers for cordless models to maximise productivity
• Torque Limiting Extensions: Precision extensions that prevent over-tightening on torque-critical applications
• Tool Bags and Cases: Protective storage solutions including branded cases and generic tool bags

Safety Information

Impact-Rated Accessories Only: Always use impact-rated sockets with black oxide finish. Standard chrome sockets can shatter under the repetitive shock loads generated by impact wrenches, creating a serious injury risk from flying fragments. The additional cost of impact sockets is a worthwhile investment in safety and longevity.

Torque Verification: For torque-critical applications such as scaffolding fixings, wheel nuts, or structural connections, never rely solely on an impact wrench. HSE guidance recommends using a calibrated torque wrench to verify that fasteners meet the required specification. Impact wrenches excel at rapid fastening, but manufacturers' quoted torque values may differ from actual delivered torque depending on battery condition, socket quality, and fastener condition.

Personal Protective Equipment: Wear safety glasses to protect against debris and fastener fragments. Impact-resistant gloves reduce vibration transmission and protect hands from sharp edges. For prolonged use, consider hearing protection as impact mechanisms generate significant noise levels.

Secure Workpieces: Ensure components are properly supported and secured before applying high torque. The sudden rotational forces can cause unsecured items to spin, potentially causing injury or damage.

Socket Retention: Check that sockets are fully seated on the drive anvil and secured with the retention pin or ring. A socket detaching under power becomes a dangerous projectile.

Battery Safety: For cordless models, only use manufacturer-approved batteries and chargers. Remove batteries during socket changes or adjustments to prevent accidental activation. Store lithium-ion batteries in cool, dry conditions away from flammable materials.

Frequently Asked Questions

What's the difference between an impact wrench and an impact driver?

An impact driver features a hexagonal bit holder designed for screwdriving applications with screwdriver bits, whilst an impact wrench has a square drive fitting that accepts socket sets for nut and bolt work. Impact wrenches typically deliver higher maximum torque and are specifically engineered for fastening applications rather than driving screws into materials.

Can I use an impact wrench to tighten wheel nuts?

Yes, impact wrenches are ideal for removing and initially tightening wheel nuts, but you must always finish with a calibrated torque wrench to achieve the manufacturer's specified torque setting. Over-tightening can damage wheel studs and make future removal difficult, whilst under-tightening creates a serious safety hazard. Many professional tyre fitters use impact wrenches for speed but verify torque manually.

What voltage cordless impact wrench do I need?

For most automotive and general trade applications, 18v models provide an excellent balance of power, runtime, and weight. Compact 12v impact wrenches suit lighter duties and confined spaces but with reduced torque output. Heavy industrial users working with larger fasteners may benefit from higher voltage platforms, though 18v technology has advanced significantly and now delivers impressive torque figures exceeding 1,000Nm in professional models.

Do I need a brushless impact wrench?

Brushless motors offer significant advantages including improved efficiency (longer runtime per battery charge), greater power output, reduced heat generation, and longer tool lifespan due to elimination of wearing carbon brushes. Whilst brushless models command a premium price, the performance benefits and reduced maintenance make them worthwhile for professional users and serious enthusiasts.

Why are impact sockets black instead of chrome?

Impact sockets undergo a different heat treatment process and are finished with black oxide rather than chrome plating. This manufacturing approach creates a slightly softer, more malleable socket that can flex slightly to absorb the repetitive shock loads from impact tools without cracking. Chrome sockets are harder but more brittle, making them unsuitable and dangerous for use with impact wrenches as they can shatter under the stress.