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Bruce L. Bergman Bruce L. Bergman is offline
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Default Impact wrench torque

On Sat, 23 Feb 2008 06:12:46 -0800 (PST), mark
wrote:

I bought what is apparently the most powerful 1/2" drive impact wrench
available IR 2135 with 1000 ftlb or torque and am still finding it
weak. The other day it would not remove the bolts that hold on my
front brake caliper bracket and sometimes it wll not remove lugnuts. I
am using it at 125psi with 50' of 3/8" hose and 1/4" M (milton) quick
connects). Would going to 3/8" qc fittings help at all? I notived a
local tire shop has the air pressure at 150 psi. Is this what is
needed? How come air tools say never to go above 90 psi?


When you are trying to push high power through air tools, the
resistance of the air line and couplers becomes critically important.
It's just like trying to run a 1000 HP dragster, but feed it fuel with
a stock VW Bug fuel pump - it just can't flow fast enough.

Do an experiment - try moving the compressor close to the car, or
vice versa. Take all the couplings out of the system - put the 3/8"
hose straight into the gun, and the other end into a 3/8 full-flow
ball valve and right into the air receiver tank.

That should be nearly free (no parts) and prove the problem.

If it does, that's the time to upgrade your air piping in the shop
to get from the tank to your workplace with a big pipe and as little
extra crap in the way as you can.

3/4" Type K extra-heavy or Type L heavy copper pipe (Not M) with as
few elbows as possible save for drip legs on each drop - your tee goes
UP from the main line before going over to the wall and down. (The
water stays in the main line, which is sloped to a drain valve.) 1/2"
or better high-flow filter-regulator-lubricator (rated for the CFM
flow of the wrench with a cushion), 1/2" QD couplings, 1/2" hoses.

* * * * * * * *

WARNING: DO NOT USE PVC PLASTIC PIPE FOR COMPRESSED AIR!! EVER!!
Even as a temporary system or for experimenting, as it tends to get
left in service far longer than intended. Hit or twist PVC pipe under
pressure and it shatters and goes "Boom!" People get hit by the
flying shrapnel and can be hurt, blinded, or occasionally killed.

* * * * * * * *

If you can't do this, consider a 5-gallon or better receiver tank as
an accumulator right next to the workplace and the impact wrench - put
the biggest hose you can from the wrench to the accumulator, and then
plumb that to your regular compressor. It will give you a burst of
full flow and full power to break the nuts loose, then you'll hit the
existing air system restrictions.

And even if you have a little "2 Sears Horsepower" portable air
compressor, throw as much air receiver tank gallonage on as you can.
The impact only needs 5 seconds of full-flow air to get that nut
moving - so what if it takes 15 minutes for the compressor to build it
back up...

The tools usually say 90 PSI Max because the internal pieces of the
hammers and anvils for the impact system start breaking if you use too
much force. They will take being used with a moderate overpressure
for a while, but do it constantly and you will see internal failures
far before their time.

-- Bruce --