--- In
DSN_KLR650@yahoogroups.com, "E.L. Green" wrote:
>
> --- In
DSN_KLR650@yahoogroups.com, "gmay131313" wrote:
> > Hi all, I just finished a valve adjustment yesterday among other
> > things on my 04 KLR and also used my 3/8 torque wrench without
> > needing any adapters..perhaps on of the real mechanics out there
> > could confirm or correct something I thought I remember being
told
> > years ago, that being if you use any type of adapter on a torque
> > wrench other then a straight extension it could give you a false
> > torque reading because of the joint binding....Now I'll have to
break
> > down and humble myself and ask one of the resident engineers here
a
> > question confirming what they have suspected all along that us
elect.
>
> Well, the joint binding certainly doesn't help, but the main issue
is
> the moment arm. Consider the word "foot/pound". 1 foot/pound of
torque
> is what you put onto a bolt if you have a one foot wrench positioned
> horizontally and hang one pound of weight off its very tip. Now,
make
> that moment arm longer, say, 1 foot 1" long via a U-joint extension,
> and how much torque are you applying? Well, you're applying slightly
> under 1.1 foot/pounds of torque -- i.e., more torque than you
thought.
> Make that moment arm shorter, by having the U-joint the other way,
so
> that the moment arm is only 11 inches long, and how much torque are
> you applying? Well, you're applying slightly over .9 foot/pounds of
> torque, or not as much torque as you thought you were applying.
>
> A torque wrench basically measures the amount of force you're
applying
> to the end of the handle of the wrench and multiplies it by the
known
> distance between the head of the wrench and its handle in order to
> present the final torque value to you, but it has no way of knowing
> you changed that distance if you add a u-joint into the equation. So
> you end up with the wrong distance in that case.
>
In one aviation application of torqueing the propeller nut on a
Stearman biplane: (paraphrased-from old brain cells)
"Propeller nut torque: 1200ft#. Place (suspend) a 200# man on a 6ft
breaker bar until the nut does not move anymore."