Re: Strange Torque Experience

[Matt Danning <mdanning@domain.elided>]

Several years ago, as part of my job at a wind turbine
manufacturing company, I spent weeks torque-testing
various sizes of bolts until they yielded, using a
torque wrench and a machine which measured the
clamping force of the bolt being tightened.

I can say for certain that using lubricated bolts
gives much more consistent clamping forces, and that
there is very little difference between lubricating
with oil or Loctite.  

I beleive that that's why (to the best of my knowlege)
all of Alfa's torque specs specify oil (or loctite) on
the threads.

How to apply Loctite?  A Loctite rep recommended a
thin bead be run along the length of the thread.  When
the bolt is tightened, the loctite will spread where
it needs to go.  Incidentally, Loctite insists the
bolts be clean and dry when the Loctite is applied.

An interesting aside:  A much more accurate method of
obtaining a a given clamping force is to use the "turn
of the nut" method--one full turn past hand tight, for
instance.  You can see that this method gives
consistent clamping forces regardless of the condition
of the threads.

Matt
LAUNCH - Your Yahoo! Music Experience
http://launch.yahoo.com
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