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Re: Bolt Tightening - Turn of the nut method
- To: <seaint(--nospam--at)seaint.org>
- Subject: Re: Bolt Tightening - Turn of the nut method
- From: "Mark D. Anderson PE" <mark(--nospam--at)alaskaengineer.com>
- Date: Tue, 9 Oct 2001 11:15:37 -0800
I would reconsider the last statement in this
reply "A similar situation prevails in
case of two sets of flanges of same material but of different thickness.
For the same T.O N the bolt tension will be higher
in the case of thicker
Actually since the T.O.N. method imposes a fixed change in
length to the bolt, occuring over the grip length, it follows that the shorter
the grip length the greater the bolt tension. As a result, the governing
specification indicates that greater nut rotation is required to achieve the
specified minimum bolt tension as the grip length increases.
Mark D. Anderson PE
----- Original Message -----
Sent: Monday, October 08, 2001 7:35
Subject: Re: Bolt Tightening - Turn of
the nut method
Christopher Wright wrote:
> If the "Turn of Nut" method is adopted for
monitoring the bolt tension is it
> not right to say that the
turn indicates the compression of the flanges
> tension in the bolt ?
Do a free body diagram of the
unloaded bolt. The internal tension in the
bolt is balanced by
equal and opposite forces an the bolt head and nut.
are in turn carried into the flanges and reacted by equal
opposite external forces on the flange which produce internal flange
compression equal to the external forces. The flange compression
therefore equals the bolt tension.
Christopher Wright P.E. |"They couldn't hit an
chrisw(--nospam--at)skypoint.com | this
distance" (last words of Gen.
The forces are definitely in equilibrium , no
What I have in mind is a little different.
Suppose we consider
two sets of flanges one made of steel
and the second one made of
aluminum. For the same amount of turn of nut
the bolt tension will
be higher in the first set flanges. The compression in the flanges
equal to bolt tension in both the cases.
A similar situation prevails in case of two sets of flanges of same
material but of
different thickness. For the same T.O N the bolt tension
will be higher
in the case of thicker flanges.
Your views please.
Regards .. raghavan