ugly post formatting! [was: my take on torque]
auditude at cox.net
auditude at cox.net
Wed Dec 3 11:58:13 EST 2003
What's up with that non-wrapped post? How do I change that? I'm using webmail, and I don't know of any options for that. There is a line width option, but it is for display, not composition.
I hit enter after each of the lines below. Maybe it'll be easier to read, not that it's fun to do. Or, maybe it'll have those stupid "=" signs throughout.
auditude at cox.net wrote:
While half-following the thread on torque and all the
answers offered, at one point I forgot what the question
was. But I think the question is how much torque is
actually applied to the crank bolt when following the manual
using the recommended tools and technique.
I'm not familiar with the math involved in calculating the
resultant torque at the bolt using the tool, which probably
has a known length. But is the math formula being disputed?
Is there more than one being offered?
To me it seems intuitive to think that any torque wrench of
any length is intended to produce the same torque at the
bolt when used as intended.
I do believe the factory tool is a torque multiplier, as
well as a way to get to the bolt without pulling too much off the front of the car.
I don't know enough about this stuff to be able to say
whether putting a pipe or extension on the handle end of a
torque wrench will affect it's accuracy. I am temped to say
that it will, since I believe you are not supposed to touch
the wrench anywhere but the handle. If I put my hand in the
middle of the torque wrench opposite the direction of force,
for example if I was pulling up on the handle, I imagine the
hand in the middle of the wrench would reduce the amount of
"handle" force getting to the bolt.
I believe the above is only relevant because were are
talking about improperly using the torque wrench. I think
the discussion about torque wrench length is totally
pointless. If you use a 2 foot torque wrench properly or
use a 2 mile torque wrench properly, the resulting torque at
the bolt is the same.
So in summary, I think the torque applied by any correctly
used torque wrench is measured at the socket. So the
question becomes, what is the torque at the bolt when the
stupid factory tool is used?
I'm sure I don't understand the rest of it (and maybe the
part above!), because there has got to be something more for
there to be such a long thread. I suspect adding length
from the socket end of the torque wrench is not the same as
adding length to the torque wrench itself. (by that I mean
using a longer torque wrench, which wouldn't change the
applied torque, but would require less force on the handle
end, and more distance)
It's possible that a simple formula for extending the lever
could be used to calculate torque. But, my hunch is that
since the "click" occurs in "the middle" of the combined
torque wrench/factory tool, instead of near the bolt, there
there is another factor to consider.
The one analogy about the four corners of the torque wrench,
pushing in four directions, seems to make a little sense. I
don't know what happens with the "extra" three directions of
force, but the only direction that the torque wrench can go
is the direction the crank bolt is turning. So, the torque
wrench is pushing the factory tool clockwise with a certain
amount of force. If that force is multiplied by the factory
tool due to its length, then it should be calculable.
Hmmm. So if the "click" point of the torque wrench is not
at the same point as the center of the bolt being tightened
(it's in between that point and the handle), then at that
point it is not measuring the "twist" that's occuring at the
bolt, but the force applied in a single direction at the
So, by using the factory tool you are moving the click point
further away from the axis of the bolt than it already is.
My conclusion is that the formula for calculating the effect
of lever length on torque should be applicable to this
problem. In other words, adding length to either side of
the click point should have the same effect, since it is
measuring force in a single direction, and not the "twist"
Make sense? Or just more talking out of asses? :P
I also believe that getting it as tight as possible with
whatever you can manage is probably fine as long as you have
More information about the quattro