That stretch is only an indicator of load was actually my point, although
made in a very random fashion. What you're suggesting is that all other
things being equal (threads, material, lube, etc) a given amount of torque
will result in equal pre-load for different length fasteners, and that the
amount of stretch resulting from that pre-load will vary depending on the
fastener length. This makes intuitive sense to me, but what about the long
head stud that get's torqued to 55#? Just different material (specs are
pretty similar) or is the "studlyness" more of factor?
Brian
At 12:09 PM 1/5/01 -0500, John.Desantis@inficon.com wrote:
>Brian wrote:
>
>One thing I've always questioned - the amount of stretch to give a certain
>amount of preload will vary depending on the length of the bolt being
>stretched,
>
>What you are missing is that stretch is not the goal, "Load" is the goal.
>A longer bolt will in fact stretch
>more for the same load than a short bolt, but at a particular torque the
>load (also called stress) should
>be the same.
>
>I assume everyone know we lube bolts so the torque we put into them does
>not get consumed
>in friction in the threads rather goes into load in the bolt.
Brian Evans
Director, Strategic Accounts
UUNET, A WorldCom Company
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