Re: Bolt

From: <Davis>
Date: Tue May 24 2005 - 09:42:00 EDT


That's a good point Eby that I had forgotten about (continuing with the fastener loosening discussion). I've seen pipefitters employ a second nut as locking method. It seems to work pretty good. Keep in mind the difference between a bolt and a stud. With a bolt, there obviously would be no reason for a "forth nut". Since a stud is a threaded rod with two loose nuts on each end, employing the extra nut for locking purposes would probably require two of them, one at each end. One of the disadvantages of this practice is the bolt/stud must be longer than would otherwise be required. Sometimes that's not feasible. But, as has been stated many times in this thread, even if the nut on the fastener is "locked", it won't do any good if it is locked at the wrong pre-load.

Hi

I observed in an existing plant the bolts where installed with three
nuts on the production headers (operating pressure 100 bar). What
could have been the reason to install the third nut. Is it to act as
lock nut?? If so why a forth nut is not on the other side. Or did it
had to do with the way it was tightened .. torqueing/ tensioning

Thanks
Eby



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[Non-text portions of this message have been removed] Received on Tue May 24 09:42:00 2005

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