This can't be right:
"I probed a bit and he said that the design depends only on the shear
strength of the bolts, not the clamp friction. So, as long as the bolts
don't fall out they should withstand the base reaction forces."
there is clearance between the bolt and the hole, right? So if there was no
friction, the tower rocks in the wind.
this leads to fatique failure of the bolts.
So: there is a friction requirement.
I think the weasel wording is that there's friction requirement for typical
winds. But that for 70mph, they don't care if the tower shifts at
the bolts.
but after a big wind, if the tower is now slightly tilted due to a shift, do
you fix it?
Or are they saying the hole vs bolt diameter is close enough, that no shifting
occurs, regardless of friction?
-kevin
ad6z
------- Original Message -------
>From : John Hudson[mailto:jd_hudson@comcast.net]
Sent : 10/13/2011 1:15:33 PM
To : towertalk@contesting.com
Cc :
Subject : RE: Re: [TowerTalk] TX-455 holes
Grant, I don't remember what type of bolts where on my tower but they did
not "look" to as heavy duty as the old bolts I had. I was worried about
breaking them off. I know I'm no were close to the 350# as KJ6Y states he's
required and I'm sure I can tighten them more. We have no requirements on
towers, YET, in western Ky. As far as "weasel wording" I've got whole other
story about UST and their weasel wording.
Thanks
73
John
KO4XJ
-----Original Message-----
Answering one of my own questions:
I called UST and got through to Remi/Remy ?? the engineer. He said "the
flange bolts should be tightened as much as the average person can
tighten them with an average wrench".
Wow - more "weasel wording" per K7LXC.. they used to have a spec, but
withdrew it.
I probed a bit and he said that the design depends only on the shear
strength of the bolts, not the clamp friction. So, as long as the bolts
don't fall out they should withstand the base reaction forces.
I've torqued my flange bolts to 130 ft-lbs and that almost brings the
flanges into tight contact.
Grant KZ1W
On 10/12/2011 10:26 PM, Grant Saviers wrote:
> Just went through the same with a new UST HDX589, 4 bolts per leg and
> wasn't sure I could get even 1 bolt into the rear leg after raising,
> pivoting on the bottom bolts in the front.
>
> However, with some struggle by threading in the first bolt, it did go
> together but did lead me to look for an appropriate 1 1/2" "spud wrench"
> on ebay that has a long tapered tail for hole alignment. I did find
> that tightening the first bolt made it possible to get in bolt 2,
> tighten it and then bolt 3 etc.
>
> Now I'm searching for the proper torque value for these bolts (1"
> A325). My engineering calcs from UST have no callouts. The Portland
> Bolt torque chart says 1063 to 1271 ft-lbs (!!!) which is going to take
> one heck of a torque wrench and several NFL linebackers. What is really
> necessary?
>
> Another question is what should the base embedded rod nuts be torqued
> to? They are 1 1/8" A36 threaded rod. If tightening against a leveling
> nut perhaps the bolts specs are the target but would that be too high if
> tightening against the embedded rod?
>
> Grant KZ1W
>
>
>
> On 10/12/2011 9:27 PM, John Hudson wrote:
>> Ok this may be irrelevant but I had a old Triesto tower that was damaged
and
>> I replaced it with a TX-455. The Triesto had 2 bolts in each leg, and
when I
>> tilted it over I pivoted on the bottom bolts in the front legs
>>
>>
>>
>> Now on the TX-455 I installed it today and got the bottom bolts in the
two
>> front legs in and raised it. Now the TX-455 has 3 bolts in each leg and
the
>> other 2 holes did not align just perfect. As a matter of fact it was
pretty
>> much a struggle to get the holes align.
>>
>>
>>
>> My question is I looked on line at some photos and looks like some use
the
>> middle holes to pivot on. Does it matter with three holes? Does it make
>> alignment any easier? Was wondering if anyone else has this issue
>>
>>
>>
>> Thanks
>>
>>
>>
>> John
>>
>> KO4XJ
>>
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
> _______________________________________________
>
>
>
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