Impact Wrenches & Impact Drivers

Impact wrench or impact driver: they are not the same tool

They get confused constantly. An impact wrench has a square anvil and drives impact sockets, and it is built for nuts and bolts: wheels, suspension, axle nuts. An impact driver has a 1/4 inch hex collet and drives bits, so it is for screws and fasteners in wood, metal and trim. Both deliver rotational hammer blows, but the wrench puts out far more torque while the driver is lighter and better controlled for repetitive fastener work. Most shops need both; most garages start with the wrench.

Choosing drive size and torque

Buying too much tool is as common a mistake as buying too little.

1/2 inch: the default

Half-inch drive covers wheels, brakes, suspension and most of what a shop does. High-torque versions handle rusted axle nuts and seized suspension bolts; mid-torque versions give up some power for a lighter, better-balanced tool that is easier to live with all day. For one impact wrench, this is the size.

3/8 inch: tight spaces

Three-eighths drive trades torque for access, which is the right trade in an engine bay or under a dash. Compact and subcompact models fit where a half-inch tool simply will not, and they still pull far harder than a hand ratchet.

3/4 inch and air tools

Three-quarter drive is for heavy truck, equipment and industrial fasteners. Air impacts still make sense where there is a compressor and constant duty: they run lighter than cordless because there is no battery, and they do not slow down as a pack drains.

Cordless or air

Cordless has taken over most automotive work because it goes where the job is, and modern brushless tools match air impacts on torque. The trade-off is weight and batteries to manage. Air stays better for high-duty-cycle shop use where a compressor already exists and tool weight matters over a full shift. If you are going cordless, pick the platform first, since batteries drive the long-term cost. Pair whatever you choose with proper impact sockets and a torque wrench for final spec, because an impact gun should never be the tool that sets final torque.