On 2/18/2014 7:00 PM, Leon wrote:
....

I don't know, I can hold the impact with a large enough socket, with my
bare hand, with a little slippage.

Because impact wrenches don't actually deliver torque, per se, but an
energy impulse. Somewhat paradoxically, against a "springy" resistance
like your hand, there is very little, if any actual torque delivered as
opposed to it working against a stuck fastener.

There's a decent albeit not fully rigorous discussion at wikipedia under
a heading "Effect of Impact Drive"...in short to transfer the hammer
action to the driven part requires an essentially elastic (the cue ball
on the object ball thingie) impact whereas your hand hold is very
non-elastic.

http://en.wikipedia.org/wiki/Impact_wrench

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