Impact Wrench
A socket driver with a hammer mechanism, sized for hex head bolts and nuts rather than screws. The tool that assembles the bolted joints this database dimensioned.
What it does
- Running down and removing hexagon head bolts and nuts
- Batch assembly of bolted joints
- Disassembly where corrosion has seized the thread
Materialswhat it is used on
All materialsFasteners it fits12 standards specify external hexagon
All standardsMatched on the drive form recorded against each standard, not on the tool's own claims — so this list changes when the fastener data changes, not when this paragraph does.
What to look forthe judgement calls, before the spec sheet
- Anvil size follows the socket range: 1/2 inch covers the common structural sizes, 3/4 and 1 inch are for heavy work where the tool needs to be able to transmit the torque at all.
- Impact-rated sockets are a different product from hand sockets. A hand socket is hard throughout and shatters; an impact socket is tougher and slightly softer, so it deforms instead of fragmenting.
- Torque is set by the trigger and the run time, so treat the tool as a way to close a gap, not as a way to reach a figure.
Misuse and safetythe ways this tool causes rework
- Every specification in this database that carries a tightening torque is out of reach for this tool — it has no way to measure what it applied. Snug with the wrench, then tighten to the figure with a torque wrench.
- Reaction torque needs somewhere to go. On a loose part it goes into your wrist; the answer is a reaction bar or a second hand, not a firmer grip.
Frequently asked questions
Does an impact wrench tighten to a controlled torque?
No. It applies a series of hammer blows whose effect depends on joint stiffness, thread friction and how long you hold the trigger. Use it to run a nut down, then finish with a torque wrench if the joint has a specified figure.
Why do impact sockets cost more than ordinary ones?
Different heat treatment. A chrome-vanadium hand socket is hard enough to crack under repeated shock; impact sockets are made to absorb it. Using a hand socket on an impact tool is a known way to put shrapnel in the workshop.
What torque does an M10 8.8 bolt need?
Around 67 N·m dry, and about 53 N·m lubricated — the difference comes entirely from thread friction. The torque calculator on this site computes the figure for the thread and class you select.