As the name suggests, impact wrenches have the ability to impart high amounts of momentum change.
The delivery of this momentum change is hard to meter, so it is quite easy to damage:
soft metals and alloys
thin threads (both male or female)
This applies to both loosening and tightening.
Take the example of spark plugs and head bolts, which screw into ...
That would be correct. There should be no issue of using the impact with the wheel off the ground. You are exactly right in that the tire should be on the ground when using a breaker bar or tire iron. The reason for this, besides the wheel spinning and you never getting the lug loosened, is because you could torque the car over and cause it to fall off of ...
Would I be right an assuming your car is equipped with alloy wheels? Also, have the wheel bolts been fitted with a small smear of grease?
It sounds like the wheel bolts are reacting in a "springy" way to the forces of the impact wrench. It may be that they're butted up tightly against the softer metal of an alloy wheel or they're in the threads with a ...
I agree wholeheartedly with both Ben and Paulster. However, I use a high-power air impact for to tighten, on it's lowest setting, and also have a selection of color "torque stix" with a minimum of three passes (snug, torque, final) while in the air. While not perfect, I think this is a reasonable compromise between my efficiency needs and returning a safe ...
4cfm is the usual rating for most air tools - including intermittent work with an impact wrench.
Also consider buying an Electric Impact Wrench (not a battery powered one - they're usually too low in power). And breaker bars with long (4ft) extensions can persuade most bolts..
Each of the impacts is like a mini lever having a go at the fastener.
If there is a longer lever, ie larger socket, there will be more force applied for the same torque applied.
So, in some cases, it’s going to be easier to undo larger fasteners than smaller fasteners with the same impact gun.