On Wed, 20 Apr 1994, John Lupien wrote:
> >4. When using a standard (normal, straight, co-linear, co-axial)
extension, use
> > your other hand to steady the T.W. at the square drive
"head" end.
>
> This is not such a good idea really. Any torque you apply with the spare
> hand will distort the reading of the torque wrench. Maybe this is a fiddly
> point, but if you care enough about the actual torque to bother using a
> torque wrench to begin with, you might as well get it exactly right...
>
The point is that the hand that steadies the t.w. at the drive end cannot
apply a torque coaxial with the bolt being torqued. When using a
conventional extension between the t.w. drive and a socket, two torques
are generated. One twists the bolt ("good" torque), while the other
applied through the extension, tries to rock the socket off of the bolt
("bad" torque). One puts his left palm against the drive head to
counteract the force that tries to rotate the socket off the head of the
bolt. If done properly, this does not affect the torque applied coaxial
with the bolt axis. Your readings will be accurate and your knuckles will
love you for it.
Ray Gibbons Dept. of Molecular Physiology & Biophysics
Univ. of Vermont College of Medicine, Burlington, VT
gibbons@northpole.med.uvm.edu (802) 656-8910
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