Torque Values, What Fastener Lubrication does.

[Judy, Stephen, & Ian]

I'll have to take your word for that. I was unable to find any reference
to dry vs. lubricated in my Bentley.
I did do a quick comparison of the specified torque for various fasteners
vs. a fitters handbook which gives bolting stress vs. torque for various
bolts (lubricated). The specified torques generally result in low (less
than 30ksi bolt stress). The gasket compression is a bit more dificult to
compute. You need to take the # of bolts X the individual bolt force /
the sealing surface area. And you need to know the recommended sealing
pressure for the gasket material. for example, 1200 psi is about right
for a 1/16" EPDM rubber gasket.
However; as a rule lubricating is still the way to go on any gasketed
joint because you will get more even compression of the gasket. And even
compression is at least as important as correct compression in gasketed
joints.
Steve

Orin Eman wrote:

> >
> > Most listed torque values in any tech manual (Bentley for example)
> > assume lubrication is used. Lubricating a bolt reduces the friction
> > between the bolt and nut threads. As a result, for a given torque a
>
> Actually, the Audi Bentleys do not assume lubrication.
> In fact, those that I have read specify _dry_.
>
> Orin.