why studs have two different threads

["Wayne Abbott" <wabbott@domain.elided>]

------------------------------

Date: Mon, 30 Dec 2002 10:21:13 -0500
From: Dana Loomis <dloomis@domain.elided>
Subject: re:  bolts and nuts

Greg Hermann wrote:

>Standard (good) design practice with studs installed in castings is to use
>a course pitch thread on the end in the casting and a fine pitch thread on
>the end meant to accept a nut.
>
>This becomes emphatically true when dealing with a light alloy casting.

>>Perhaps he'd also be willing to explain why is this so important.  I'd
like
>>to understand.

>>Dana Loomis
Dana,
Fine threads can be tightened with less torque, or something like that.  It
is like walking up the gentle slope rather than the steep slope.  Course
threads, the steeper incline, remember a thread is just a long spiral
incline, will resist pulling out or stripping more than the fine threads.

So you stick the course threaded, pull out resistant end of the stud into
the soft aluminum, install the part over the stud(s) and tighten with the
gently sloping spiral incline threaded end, or something like that.  So i've
been told.

Wayne Abbott
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided