Looking at the documentation from most of the quality manufacturers of
torque wrenchs (Proto, Snap-on, Norbar, etc..) I see that I can
increase the "range" of a torque wrench by putting an "in-line"
extension on the *drive* end(not the handle end. By scaling the
reading/click setting accoring to a formula which accounts for the
length of the extension, one can apply a torque that is greater than
the wrench would do if there was no extension. (Just so I'm clear,
this is not the typical sort of extension that goes perpendicular to
the wrench, but is instead in line with the axis of the wrench.)

Now - I've searched far and wide and cannot find anyone who actually
makes or sells a simple extension that I can buy. I'm looking for one
that has a 1/2" square female socket on one end (where the drive end
of the torque wrench fits) with a 1/2" male square drive on the other
end. I've seen ones where the drive ends are open-ended spanners, box
ends, etc, but can't find a simple square-square adapter.

Here'a a link to a guy who's built a homemade version:
http://www.specialpatrolgroup.co.uk/...ue/torque.html

Of course, I could build one or have one built, but this seems so
obvious that somebody's got to be making such a thing. Lengths from
6" to 24"(+) would be OK for my needs.

Anybody have a source for such a thing?

-Dave

Are you referring to a "torque multiplier"? If so, search Google for plenty
of sources. Here's one, but I have a feeling the link won't work:

http://www.torquestick.com/cart/cust...99dba310b28293

"djl" wrote in message
om...
Looking at the documentation from most of the quality manufacturers of
torque wrenchs (Proto, Snap-on, Norbar, etc..) I see that I can
increase the "range" of a torque wrench by putting an "in-line"
extension on the *drive* end(not the handle end. By scaling the
reading/click setting accoring to a formula which accounts for the
length of the extension, one can apply a torque that is greater than
the wrench would do if there was no extension. (Just so I'm clear,
this is not the typical sort of extension that goes perpendicular to
the wrench, but is instead in line with the axis of the wrench.)

Now - I've searched far and wide and cannot find anyone who actually
makes or sells a simple extension that I can buy. I'm looking for one
that has a 1/2" square female socket on one end (where the drive end
of the torque wrench fits) with a 1/2" male square drive on the other
end. I've seen ones where the drive ends are open-ended spanners, box
ends, etc, but can't find a simple square-square adapter.

Here'a a link to a guy who's built a homemade version:
http://www.specialpatrolgroup.co.uk/...ue/torque.html

Of course, I could build one or have one built, but this seems so
obvious that somebody's got to be making such a thing. Lengths from
6" to 24"(+) would be OK for my needs.

Anybody have a source for such a thing?

-Dave

"djl" wrote in message
om...
Looking at the documentation from most of the quality manufacturers of
torque wrenchs (Proto, Snap-on, Norbar, etc..) I see that I can
increase the "range" of a torque wrench by putting an "in-line"
extension on the *drive* end(not the handle end. By scaling the
reading/click setting accoring to a formula which accounts for the
length of the extension, one can apply a torque that is greater than
the wrench would do if there was no extension. (Just so I'm clear,
this is not the typical sort of extension that goes perpendicular to
the wrench, but is instead in line with the axis of the wrench.)

Now - I've searched far and wide and cannot find anyone who actually
makes or sells a simple extension that I can buy. I'm looking for one
that has a 1/2" square female socket on one end (where the drive end
of the torque wrench fits) with a 1/2" male square drive on the other
end. I've seen ones where the drive ends are open-ended spanners, box
ends, etc, but can't find a simple square-square adapter.

Here'a a link to a guy who's built a homemade version:
http://www.specialpatrolgroup.co.uk/...ue/torque.html

Of course, I could build one or have one built, but this seems so
obvious that somebody's got to be making such a thing. Lengths from
6" to 24"(+) would be OK for my needs.

Anybody have a source for such a thing?

-Dave

I seem to recall an adapter much like you describe with a gearing multiplier
inside. I don't remember who made it. It was basically a transmission of
sorts with planet gears.

Hmm.. my internet search brought up this.

http://www.torqtech.com/torque_multipler.htm

-Bruce

I think the example in the spooky-torque design is probably considerably
inaccurate for a couple of reasons.

Beam deflection, like the principle of a beam-type torque wrench. Depending
upon the choice of material, the amount of deflection could change with use.
As the deflection changes (from a straight line), so does the distance to
the center of the far end.
The breaker bar swivel pin and yoke deflection.

Maybe the best chance at achieving a predictable multiplier would be a
single piece of very strong material (no fasteners or joints), and the
centerline kept perfectly straight, while keeping the axis of the torque
wrench drive at precisely 180 degrees to the drive socket.

I don't think an accurate torque reading/indication can be achieved with a
breaker bar and/or the extension shown in the example.
There wouldn't be an easy way to test the accuracy of a homemade extension
without having it checked against a calibrated standard.

WB
..................

"djl" wrote in message
om...
Looking at the documentation from most of the quality manufacturers of
torque wrenchs (Proto, Snap-on, Norbar, etc..) I see that I can
increase the "range" of a torque wrench by putting an "in-line"
extension on the *drive* end(not the handle end. By scaling the
reading/click setting accoring to a formula which accounts for the
length of the extension, one can apply a torque that is greater than
the wrench would do if there was no extension. (Just so I'm clear,
this is not the typical sort of extension that goes perpendicular to
the wrench, but is instead in line with the axis of the wrench.)

Now - I've searched far and wide and cannot find anyone who actually
makes or sells a simple extension that I can buy. I'm looking for one
that has a 1/2" square female socket on one end (where the drive end
of the torque wrench fits) with a 1/2" male square drive on the other
end. I've seen ones where the drive ends are open-ended spanners, box
ends, etc, but can't find a simple square-square adapter.

Here'a a link to a guy who's built a homemade version:
http://www.specialpatrolgroup.co.uk/...ue/torque.html

Of course, I could build one or have one built, but this seems so
obvious that somebody's got to be making such a thing. Lengths from
6" to 24"(+) would be OK for my needs.

Anybody have a source for such a thing?

-Dave

If your interested I have a 3/4" drive for sale reasonable, haven't used
it much.. if interested e-mail me
Paul

djl wrote in message
om...
Looking at the documentation from most of the quality manufacturers of
torque wrenchs (Proto, Snap-on, Norbar, etc..) I see that I can
increase the "range" of a torque wrench by putting an "in-line"
extension on the *drive* end(not the handle end. By scaling the
reading/click setting accoring to a formula which accounts for the
length of the extension, one can apply a torque that is greater than
the wrench would do if there was no extension. (Just so I'm clear,
this is not the typical sort of extension that goes perpendicular to
the wrench, but is instead in line with the axis of the wrench.)

Now - I've searched far and wide and cannot find anyone who actually
makes or sells a simple extension that I can buy. I'm looking for one
that has a 1/2" square female socket on one end (where the drive end
of the torque wrench fits) with a 1/2" male square drive on the other
end. I've seen ones where the drive ends are open-ended spanners, box
ends, etc, but can't find a simple square-square adapter.

Here'a a link to a guy who's built a homemade version:
http://www.specialpatrolgroup.co.uk/...ue/torque.html

Of course, I could build one or have one built, but this seems so
obvious that somebody's got to be making such a thing. Lengths from
6" to 24"(+) would be OK for my needs.

Anybody have a source for such a thing?

-Dave

Sure, beam deflection, and other "slop" in the setup does induce
error. As you suggest, I'm intending to minimize that error by having
it deflect as little as possible - both mimimizing length (I only need
6-10 inches, really, to get to the torque ranges I'm after) and making
sure it's as stiff as possible.

That said, even if the setup were to deflect, say, 15deg, cosine error
induced would be about 3.5%. Overall effect on the system is
dependent on the relative length of the extension compared to the
wrench. If I were to really worry about it, it's pretty a pretty
simple trig problem to figure out exactly how much cosine error I have
(by measuring actual beam deflection) and factor that back into my
torque wrench click setting. Also consider that my *calibrated*
wrench is only certified to 4% accuracy anyway. All said, it's well
within the range of accuracy I need where the torque specs required
are on the order of +/- 15% - it's just not that critical of an
application.

As to verifying torque, one can get a good check by clamping the setup
in a solid vise and applying known weights to the extension/wrench
combo. Measure the distance and you know if you're in the ballpark or
not.


"Wild Bill" wrote in message
I think the example in the spooky-torque design is probably considerably
inaccurate for a couple of reasons.

Beam deflection, like the principle of a beam-type torque wrench. Depending
upon the choice of material, the amount of deflection could change with use.
As the deflection changes (from a straight line), so does the distance to
the center of the far end.
The breaker bar swivel pin and yoke deflection.

Maybe the best chance at achieving a predictable multiplier would be a
single piece of very strong material (no fasteners or joints), and the
centerline kept perfectly straight, while keeping the axis of the torque
wrench drive at precisely 180 degrees to the drive socket.

I don't think an accurate torque reading/indication can be achieved with a
breaker bar and/or the extension shown in the example.
There wouldn't be an easy way to test the accuracy of a homemade extension
without having it checked against a calibrated standard.

Nope - not looking for a geared multipler. Just a simple bar with
socket adapters at each end.


"Bruce Chang" wrote in message
I seem to recall an adapter much like you describe with a gearing multiplier
inside. I don't remember who made it. It was basically a transmission of
sorts with planet gears.

http://www.torqtech.com/torque_multipler.htm

djl wrote:

Sure, beam deflection, and other "slop" in the setup does induce
error. As you suggest, I'm intending to minimize that error by having
it deflect as little as possible - both mimimizing length (I only need
6-10 inches, really, to get to the torque ranges I'm after) and making
sure it's as stiff as possible.




Why don't you just buy a right sized torque wrench? If it's important
enough to be torqued to spec isn't it important enough to have the
proper tool?


I have to wonder if your an engineer (unlikely) or in management (that's
my guess).





--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

Mark -

Whoa - the personal dig is uncalled for. That aside - the inquiry is
legit.

Given that Proto, Norbar, Sturtevant-Richemont, and Mountz - all of
which are highly respected manufacturers of torque equipment -
document procedures and calculation formulas for using such
extensions, it is only reasonable that this general approach is valid.
This is not just a hack - see some links below. The principles
involved, the limitations (sources of error) and, most importantly,
the needs of this particular application are understood, including
those of cost. This *is* good engineering practice.

So - I'm just looking for a source. Get it?

-Dave

http://www.norbar.com/FAQ.htm#TWExtensions - supplier for Ferrari F1
race team
http://www.mountztorque.com/html/body_calculations.htm - supplier
http://www.akotorque.com/usefull.htm - supplier of torque calibration
equipment
http://www.marinemechanic.com/site/page128.html
http://www.stanleyproto.com
(there's lots more out there, check for yourself)


Mark wrote in message ...


Why don't you just buy a right sized torque wrench? If it's important
enough to be torqued to spec isn't it important enough to have the
proper tool?

I have to wonder if your an engineer (unlikely) or in management (that's
my guess).

Mark

N.E. Ohio

In article , djl says...

Now - I've searched far and wide and cannot find anyone who actually
makes or sells a simple extension that I can buy. I'm looking for one
that has a 1/2" square female socket on one end (where the drive end
of the torque wrench fits) with a 1/2" male square drive on the other
end.

I would consider purchasing two 1/2 inch breaker bars, the kind
with the round sliding male half inch square drive.

Then grind off the retaining balls on one side of each one,
and slide the square drive unit off of one, and onto the
other.

So now you have two square sliding male fittings. Step
one would be immobilize them on the bar with, say, braze.
Be sure they are pointing in opposite directions.

Step two is find the correct size 12-point socket that fits
a half inch square. I think there is a very close match
iirc.

Then the existing torque wrench goes into the 12-point
socket, and the socket you want to use goes on the other
male end.

Key to making this work is purchasing the items used or
otherwise, inexpensively.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

djl wrote:
Mark -

Whoa - the personal dig is uncalled for. That aside - the inquiry is
legit.

Given that Proto, Norbar, Sturtevant-Richemont, and Mountz - all of
which are highly respected manufacturers of torque equipment -
document procedures and calculation formulas for using such
extensions, it is only reasonable that this general approach is valid.
This is not just a hack - see some links below. The principles
involved, the limitations (sources of error) and, most importantly,
the needs of this particular application are understood, including
those of cost. This *is* good engineering practice.

So - I'm just looking for a source. Get it?



I knew what you were getting at before you asked the question.

I have more than a passing familiarity with the use of fixtures and
extensions on torque wrenches.

Extensions are only used to gain access to fasteners that are otherwise
inaccessible. Period.

The use of an extension may be mathematically sound and 'good
engineering practice'. That's why it's usually a good thing to keep many
engineers away from the work. Keeps them from doing too much damage.

It is an unacceptable practice, or at least extremely poor form for a
technician to use an extension solely to increase the range of the
torque wrench. We know better.

And the fact your having such a difficult time finding what your looking
for should give you a clue.


Get it?


Suck it up. Buy the correct tooling.



--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

Mark wrote: (clip) The use of an extension may be mathematically sound and
'good engineering practice'. That's why it's usually a good thing to keep
many engineers away from the work (clip) Get it? Suck it up. Buy the correct
tooling.
^^^^^^^^^^^^^
Stubbornness is no substitute for thinking. djl has explained his need, and
allowed for the minor inaccuracies that could result from the use of an
extension. Let's face it--most of us do not require Bureau-of-Standards
accuracy when we tighten a bolt. But, I guess that engineers, using
accepted mechanical theory, know less than you do.

jim rozen wrote: (clip) Then the existing torque wrench goes into the
12-point socket, and the socket you want to use goes on the other male end.
Key to making this work is purchasing the items used or otherwise,
inexpensively
^^^^^^^^^^^^^^
That idea might be less expensive to carry out if you just welded a 1/2"
drive socket to the end of a 1/2" breaker bar.

I could have used one a few weeks ago...

Its been a long time since I've seen the catalogs, but I suspect the Kent
Moore tool company - which used to (or maybe still does) make specialty
tools for GM - had what you are looking for.

Good Luck!

djl wrote:

Looking at the documentation from most of the quality manufacturers of
torque wrenchs (Proto, Snap-on, Norbar, etc..) I see that I can
increase the "range" of a torque wrench by putting an "in-line"
extension on the *drive* end(not the handle end. By scaling the
reading/click setting accoring to a formula which accounts for the
length of the extension, one can apply a torque that is greater than
the wrench would do if there was no extension. (Just so I'm clear,
this is not the typical sort of extension that goes perpendicular to
the wrench, but is instead in line with the axis of the wrench.)

Now - I've searched far and wide and cannot find anyone who actually
makes or sells a simple extension that I can buy. I'm looking for one
that has a 1/2" square female socket on one end (where the drive end
of the torque wrench fits) with a 1/2" male square drive on the other
end. I've seen ones where the drive ends are open-ended spanners, box
ends, etc, but can't find a simple square-square adapter.

Here'a a link to a guy who's built a homemade version:
http://www.specialpatrolgroup.co.uk/...ue/torque.html

Of course, I could build one or have one built, but this seems so
obvious that somebody's got to be making such a thing. Lengths from
6" to 24"(+) would be OK for my needs.

Anybody have a source for such a thing?

-Dave

In article , Leo
Lichtman says...


jim rozen wrote: (clip) Then the existing torque wrench goes into the
12-point socket, and the socket you want to use goes on the other male end.
Key to making this work is purchasing the items used or otherwise,
inexpensively
^^^^^^^^^^^^^^
That idea might be less expensive to carry out if you just welded a 1/2"
drive socket to the end of a 1/2" breaker bar.

It all depends what one has available in the junk box.

But whatever he does, *don't* weld the items together.
I've found that the HAZ becomes brittle sometimes that
way, and the tool will snap at the weld. Brazing is
really better.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

Mark wrote in message ...

No flame fests for me - the kill file is getting its first entry in
many, many years.

-Dave

Leo Lichtman wrote:

Let's face it--most of us do not require Bureau-of-Standards
accuracy when we tighten a bolt. But, I guess that engineers, using
accepted mechanical theory, know less than you do.



Many times yes, they do know less.

That's not arrogance, it's an observation.

Seems many engineers think their degree means they know what their doing
instead of what it truly is, a learners permit.


Bureau of Standards accuracy? Damned straight. If it didn't matter there
wouldn't be calibration expiration dates on our tools.




--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

The induced error comes from the torque wrench you use and the
accuracy of the length measuresments on BOTH the wrench and the
extentions. Slop and deflections (within reason) do not affect
it. But the error is doubled so a +/- 4% of FULL SCALE becomes
+/- 8% of full scale. A 150 ft pound wrench at +/- 4% with a
doubler extension becomes +/- 12 foot pounds. If that is within
your tolerance, go for it.

If you want to argue about calibration, it is always a good
thing. But how many auto dealerships take the time to go through
all the mechanic's toolboxes and calibrate the various torque
wrenches?

In the industrial setting, it is common to send an inspector
around to all the tool boxes and ban or confiscate out of
tolerance dial indicators, tape mesures, etc.

djl wrote:

Sure, beam deflection, and other "slop" in the setup does induce
error. As you suggest, I'm intending to minimize that error by having
it deflect as little as possible - both mimimizing length (I only need
6-10 inches, really, to get to the torque ranges I'm after) and making
sure it's as stiff as possible.

That said, even if the setup were to deflect, say, 15deg, cosine error
induced would be about 3.5%. Overall effect on the system is
dependent on the relative length of the extension compared to the
wrench. If I were to really worry about it, it's pretty a pretty
simple trig problem to figure out exactly how much cosine error I have
(by measuring actual beam deflection) and factor that back into my
torque wrench click setting. Also consider that my *calibrated*
wrench is only certified to 4% accuracy anyway. All said, it's well
within the range of accuracy I need where the torque specs required
are on the order of +/- 15% - it's just not that critical of an
application.

As to verifying torque, one can get a good check by clamping the setup
in a solid vise and applying known weights to the extension/wrench
combo. Measure the distance and you know if you're in the ballpark or
not.


"Wild Bill" wrote in message

I think the example in the spooky-torque design is probably considerably
inaccurate for a couple of reasons.

Beam deflection, like the principle of a beam-type torque wrench. Depending
upon the choice of material, the amount of deflection could change with use.
As the deflection changes (from a straight line), so does the distance to
the center of the far end.
The breaker bar swivel pin and yoke deflection.

Maybe the best chance at achieving a predictable multiplier would be a
single piece of very strong material (no fasteners or joints), and the
centerline kept perfectly straight, while keeping the axis of the torque
wrench drive at precisely 180 degrees to the drive socket.

I don't think an accurate torque reading/indication can be achieved with a
breaker bar and/or the extension shown in the example.
There wouldn't be an easy way to test the accuracy of a homemade extension
without having it checked against a calibrated standard.

djl wrote:

No flame fests for me - the kill file is getting its first entry in
many, many years.




Sorry, I didn't realize you had such a fragile ego.





--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

In article ezdBb.343793$275.1138346@attbi_s53,
AL wrote:
Are you referring to a "torque multiplier"? If so, search Google for plenty
of sources. Here's one, but I have a feeling the link won't work:

http://www.torquestick.com/cart/cust...99dba310b28293

It worked for me (with careful cut and paste work), but this
does not look like what the original poster is looking for.

This is a geared torque converter.

What he is looking for is an extension which offsets the socket
by a precise distance. When set in line with the bar of the torque
wrench, and extending past the head. The effect is to add length to the
wrench, so the torque reading is actually lower than the actual torque
applied at the end of the effectively longer lever.

As others have pointed out, while this extends the range of the
wrench, it reduces the accuracy. And if the extension is not in proper
line with the main shank of the torque wrench.

The way this works is that you need to apply a given force on
the torque wrench handle (at a precise distance from the socket). The
wrench is actually measuring the force. By extending the socket to
beyond the head, you are applying that force on a longer lever, you are
producing proportionally more torque at the actual socket.

What you found is probably a better choice in reality -- but is
certainly more expensive. If the original poster is looking for this to
keep costs down, and does not care about the loss of accuracy, what he
is looking for is probably the best choice -- btu I'' bet that he could
find a torque wrench to cover the range that he needs by a quick eBay
search, and keep the costs way down that way.

I'm set, up to 600 ft-lbs, thanks to a surplus sale many years
ago.

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
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