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Posted by F. George McDuffee on February 23, 2008, 4:37 pm
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On Sat, 23 Feb 2008 09:52:17 -0800, Larry Jaques
>On Sat, 23 Feb 2008 11:03:19 -0600, with neither quill nor qualm, F.
>
>>On Sat, 23 Feb 2008 11:46:26 -0500, Joseph Gwinn
>>
>>>What torque is your arm rated for? It seems unlikely that any human can
>>>put a 1000# push on a handheld tool that might be 12" in diameter at
>>>most.
>>==============
>>There is a reason these are called *IMPACT* guns
>
>Yabbut, methinks the 1,000# figure is calculated using Searz Foot
>Pounds. I doubt a 1/2" gun would do better than 300, with a 3/4 or 1"
>drive capable of doing up to 1k.
=================
From limited experience but having done it, a 1/2 inch gun on
90-100 PSI w/ adequate flow will shear off a "normal" automotive
lugnut/stud (or lug bolt) if the nut jams or rusts on.
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Posted by on February 23, 2008, 9:07 pm
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On Sat, 23 Feb 2008 09:52:17 -0800, Larry Jaques
>On Sat, 23 Feb 2008 11:03:19 -0600, with neither quill nor qualm, F.
>
>>On Sat, 23 Feb 2008 11:46:26 -0500, Joseph Gwinn
>>
>>>What torque is your arm rated for? It seems unlikely that any human can
>>>put a 1000# push on a handheld tool that might be 12" in diameter at
>>>most.
>>==============
>>There is a reason these are called *IMPACT* guns
>
>Yabbut, methinks the 1,000# figure is calculated using Searz Foot
>Pounds. I doubt a 1/2" gun would do better than 300, with a 3/4 or 1"
>drive capable of doing up to 1k.
>
Yabbut, yathinks wrong.
>---
>Every moment is a golden one
>for him who has the vision to recognize it as such.
> -- Henry Miller
--
Posted via a free Usenet account from http://www.teranews.com
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Posted by Larry Jaques on February 24, 2008, 8:40 am
Please log in for more thread options On Sat, 23 Feb 2008 21:07:01 -0500, with neither quill nor qualm,
clare at snyder.on.ca quickly quoth:
>On Sat, 23 Feb 2008 09:52:17 -0800, Larry Jaques
>>Yabbut, methinks the 1,000# figure is calculated using Searz Foot
>>Pounds. I doubt a 1/2" gun would do better than 300, with a 3/4 or 1"
>>drive capable of doing up to 1k.
>
>Yabbut, yathinks wrong.
That was deep and enlightening. <snort>
OK, checking online, CP (my recollection of the finest product) shows
their top of the line 1/2" impact gun, the CP 749-2, putting out 625
ft# of torque. That amazes me.
I still think the 1000# is a bunch of marketing shit. Air gun
technology doesn't appear to have changed much since I was using them
on a daily basis.
---
Every moment is a golden one
for him who has the vision to recognize it as such.
-- Henry Miller
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Posted by on February 23, 2008, 9:02 pm
Please log in for more thread options On Sat, 23 Feb 2008 11:46:26 -0500, Joseph Gwinn
>In article
>
>> I bought what is apparently the most powerful 1/2" drive impact wrench
>> available IR 2135 with 1000 ftlb of torque and am still finding it
>> weak.
>
>What torque is your arm rated for? It seems unlikely that any human can
>put a 1000# push on a handheld tool that might be 12" in diameter at
>most.
>
>Joe Gwinn
The mass of the wrench absorbs the "instantanious torque" or "impact".
Mean torque, or average torque, may be as little as 100-150 ft lbs and
still have a 1000 ft lb rating - without stretching things at all (or
very little)
>
>
>> 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?
--
Posted via a free Usenet account from http://www.teranews.com
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Posted by Joseph Gwinn on February 24, 2008, 11:46 am
Please log in for more thread options clare at snyder.on.ca wrote:
> On Sat, 23 Feb 2008 11:46:26 -0500, Joseph Gwinn
>
> >In article
> >
> >> I bought what is apparently the most powerful 1/2" drive impact wrench
> >> available IR 2135 with 1000 ftlb of torque and am still finding it
> >> weak.
> >
> >What torque is your arm rated for? It seems unlikely that any human can
> >put a 1000# push on a handheld tool that might be 12" in diameter at
> >most.
> >
> >Joe Gwinn
>
> The mass of the wrench absorbs the "instantanious torque" or "impact".
> Mean torque, or average torque, may be as little as 100-150 ft lbs and
> still have a 1000 ft lb rating - without stretching things at all (or
> very little)
OK, makes sense. Same theory as the traditional striking wrenches. But
the wrench must be pretty heavy to achieve such a number.
But I still suspect that the 1000# may be a better measure of their
marketing versus their impact wrenches. The instantaneous peak torque
one will achieve will depend on how stiff the nut assembly in question
is. I assume that this is measured while trying to twist a piece of hex
stock welded to an anvil-sized hunk of iron. A better measure might be
the rotational inertia of the hammer assembly plus the rotational speed
at impact, combined into the angular momentum at impact. Such a measure
would be more useful in deciding the relative strength of an impact
wrench.
Hmm. The above metric won't work. A very light hammer moving fast will
have a large angular momentum, but will be ineffectual in breaking stuck
fasteners loose - the hammer will just bounce. The surface may become
battered, but the nut won't turn. The hammer must be heavy, just as
when using a handheld hammer to force something apart by banging on it.
Or a handheld hammer-activated impact wrench. I always used at least a
two-pound hammer, sometimes five pound. The objective was to use a
sufficiently large hammer that one blow would reliably do the job. This
is how I got aluminum screws out of aluminum castings without damage, to
get the alternator cover off of 1970s Japanese bikes. You got one
chance before the #2 phillips screw was mangled beyond hope. They came
loose with a very loud Crack!
This requires some thought. There must be a metric that captures the
effect of hammer weight on effectiveness.
Joe Gwinn
> >> 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?
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