Can you tell me how Torq Sticks Work?

On Sat, 5 Mar 2005 18:52:43 -0600, "HLS" > wrote:

>
>"Lawrence Glickman" > wrote in message
.. .
>> On Fri, 4 Mar 2005 13:16:26 -0600, "HLS" > wrote:
>>
>> >Didn't you recently shell out for a digital Sears torque tester,
>Lawrence?
>> >
>>
>> Yes HLS, I did in fact do so. Now today I bought a real torque wrench
>> and am mounting the strain gauge and associated torque meter to my
>> workbench so I can know how far off my *real* torque wrench is
>> calibration wise. The New torque wrench I bought today.
>>
>> I used the gauge on the car once, it went flawlessly, but, it is
>> _expensive_ and a relatively sensitive piece of equipment, so I'll use
>> it for calibration in the house and leave the down and dirty stuff to
>> my new clicker.
>>
>> Lg
>
>Have you used it to calibrate the TorkStix?

TorkStix went back, and I got an impulse wrench instead ( aka
"clicker" ).

As far as I can tell, the markings on the impulse wrench are pretty
close to accurate. within a few pound-feet up to 80 which is where I
stopped measuring, as at that point, my workbench was rotating ;-)

>Personally, I don't worry about it too much. I keep my torque wrench well
>protected, and assume that if I get everything pretty much balanced and near
>the spec value, that I will be okay. Has worked out ok up to now....

I used to think the same way, but when I checked an old but pampered
torque wrench against my strain gauge, it was 16 ft/lbs off at one
point. So rather than spend the $50 to get it recalibrated, I just
use it as a breaker bar now and bought a New torque wrench.

>Now, it is important that one know the torque specs...several years ago a
>professional mechanic and I were replacing head gaskets on a 429 Ford.. In
>this
>case, he told me to torque the bolts at about 85-90 ft-lbs. He hadn't
>checked the specs.
>
>The next day or two, the car came back. Another blown gasket. Upon
>checking, the head bolt torque specs were 140 ft-lbs. Took all my glutei to
>get there, but it was the magic number.

That's a lot. I would most likely use a piece of pipe as an extension
for that kind of force.

>In general, you don't have to be exact, but you have to be near, and you
>have to
>be consistent.
>
>Best regards

I agree things should be balanced, but if you under torque you blow
head gaskets or things come loose and fall apart, and if you over
torque you break bolts. So you do have to be close to specs or things
aren't going to work out.

When I get a range, like 85 to 105 for something, I set up for the
middle of that <95> to allow for any imperfections in the calibration.

I'll rarely find anything that gives an _exact_ specification, +/-
nothing, it seems there is always a range, and I aim for the middle of
it.

Best,

Lg