I've been holding my tongue (fingers?) on this so far, but am finally
compelled to comment. I am a *serious* user of Loctite products (some I
buy by the liter) and of antiseize, and each has its place. I've been
working on cars, mostly old ones, as an amateur and as a professional
for close to 40 years. I almost never use Loctite on threaded fasteners
in castings unless I'm trying to solve a specific problem. I'll
intersperse some comments after a little deletion:
Susan and John Roper wrote:
>
(snip Nils' pretty good summary of situation)
>
> Nils, I don't mean to be testy, and perhaps we don't disagree. My
> experience, and I have been aroung a long time, is that studs break not
> because of fatigue, but becaues of poor metallurgy(Italian stuff), from
> overtightening which stretches and reduces diameter, and because of nuts
> that seize on the stud by corrosion.
====
If I encounter a broken stud I really don't care what the exact
mechanism of failure was. I care about getting it out and keeping it
from happening again. But as to the last cause--if the seized nut caused
the stud to break, then the stud was *stuck* in the casting--otherwise
the stud would have unscrewed--and that's exactly the problem we're
trying to avoid.
>> If you do not secure the stud in
> the casting, then you will more often than not withdraw the stud rather
> than removing the nut, which in certain applications can be a problem.
====
I'm having a hard time imagining a situation in which this would not be
a mere inconvenience rather than a problem. Simply remove the nut from
the stud, or replace both with new parts, and put the stud back in. If I
have a choice between the stud unscrewing or damage to the fastening
system occurring, I'll take the unscrewed stud *every time.* So in any
application where heat or water is likely to cause long-term problems, I
use anti-seize with an appropriate reduction in torque values.
>
> Thus I prefer to secure the stud, which loctite does well. That will
> not solve the problem of corrosion outside the casting, but will provide
> a stud that is both secure and removable. That is my preference. To
> each his own. John
====
Yes, indeed. "My own" is to make assemblies that can be serviced easily
next week, next year or next decade. Or even next century!!! (Don't know
if I'd say that in three years, though.)
Joe
--
Heather & Joe Way
Sierra Specialty Automotive
Brake cylinders sleeved with brass
Delco alternator One-Wire conversions
Quincy, CA
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