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Subject:Re: 250 ft-lb torque wrench?
From:George Goff
Date:Fri, 28 Mar 2003 08:34:11 EST

In a message dated 3/28/03 6:31:24 AM, caryccc@JUNO.COM writes:

<< . . . why does the lever need to be horizontal when measuring torque?  The
length of the lever is the same at any angle, and the force applied will be
perpendicular to the lever, right? >>

No.  This torque which we are talking about is the magnitude of the moment
about a point.  Trying my damnedest to avoid adding any new terms to the mix,
the "torque" is the product of the magnitude of the applied force times the
perpendicular distance from the point to the line of action of the force.  A
lever of any length might be used to place the force anywhere along its line
of action but the length of the real "lever" is the distance from the center
of rotation to the line of action on a line perpendicular to the line of
action.

I can see this is getting out of control.  So, if you can't resolve the
applied force into its tangent component, then, whenever you are tightening
that rear axle nut just put your foot into a rope stirrup hung from a cheater
the calculated distance and stop whenever the bar is horizontal.  That way
the force (your weight) will be a known perpendicular distance from the
center.

George