[TowerTalk] FW: UST bolt Torque question

[Grant Saviers]

One leg of a self supporting tower falls "up" - it fails in tension.
My nuts are tight after torquing bolts to 140 ft-lbs...

Grant KZ1W


On 6/25/2013 12:59 PM, Mitchell, Dennis C wrote:
> "I've never seen a Tower fall UP."
> I'd only torque bolts enough to keep your nuts from falling off...
>
> K8UR
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of KM5VI
> Sent: Tuesday, June 25, 2013 3:28 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] FW: UST bolt Torque question
>
> Snug tight is a standard term commonly used in the design of bolted connections that are not slip-critical.  Slip-critical connections rely on the friction created by the clamping action of the threaded connection and require a minimum fastener torque or bolt stretch specification to achieve the design friction value.  Bolted connection design based on the simple shear and/or bearing strength of the fastener do not rely on joint friction, and thus the assembly torque is non-critical provided that it is tight enough to eliminate slop in the joint that might over time from load cycles (bolt loosening).
>
> FYI - I have found a spud wrench useful for snug tight connections on my crank-up tower base connections - it is a short wrench that is designed to be struck with a hammer.
>
> Hope this helps.
>
> Matt
> KM5VI
>
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> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim Thomson
> Sent: Tuesday, June 25, 2013 7:39 AM
> To: towertalk at contesting.com
> Subject: [TowerTalk] UST bolt Torque question
>
>
> I asked UST  how much Torque should be used on both the 12 x  1.125 inch anchor rods....and also the 18 x  1 inch leg bolts.
> I also told em I used never seize on both anchor rods and legs bolts.  Also told em the anchor rods are 104 ksi yield strength..and came from portland bolt...and are 60 inchs long each.... with 6 inch threads
> on each end.   Told em that the 18 x leg bolts are
> A325 bolts and are 3 inchs long each.    Everything has heavy duty flat
> washers and slightly oversized nuts on em.
>
> Their reply was...... snug fit !    This is for my UST  HDX-689 tower.  This
> is the old style 689..that weighs 5000 lbs..without the ants and mast, but that
> weight includes the bearings  and small  PP  rotor.   The crane operator
> weighed the tower when it was unloaded.
>
> What is  ..snug fit ?     Trying to get  answers from UST at times can be
> exasperating.
> Does anybody even know ?    I was thinking  perhaps  125 ft lbs for the
> anchor rods......and 100 ft lbs for the leg bolts.   Leg bolts can always be
> replaced...
> anchor rods cant.
>
> Tnx...  Jim   VE7RF
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