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Author Topic: Tower installation to use washers or not ?  (Read 15255 times)
NV2A
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Posts: 139




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« Reply #15 on: August 13, 2014, 06:26:40 PM »

I have 1" stainless bolts sticking out of the cement bases.  I placed 1 nut on each of those bolts and then a "two" heavy washers and then my 5/8 plate steel base with tabs welded within an inch or so of the bolt holes for the towers tilt assembly to mount to.  Once the plate is down I drop a large washer over each of the bolts, puton the nuts and tighten down the base with a 1/2 drive breaker bar.  I don't have a torque wrench that size but I put so much body weight into each bolt so as to make an attempt to get them all similarly tight.

Similarly tight nuts is quite important if you don't want one loose one to start coming undone and compromising the others.  I like the use of washers as they allow you to get the bolts tighter (no kidding) and they distribute the load (the nut) over a broader area then just what ever the nut can grab of your plate.  I think what the manufacture is saying "in our opinion you don't have to use washers" as opposed to "don't use washers, they will weaken the structure". 

Having said all that, in the event of a catastrophic failure and "possible" subsequent lawsuit, it would be nice to be able to tell the judge and put the ball in the manufacturers court by saying you followed their instructions to the letter.
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N9RD
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« Reply #16 on: August 13, 2014, 09:34:08 PM »

Ray, I felt the same way about mounting my tower base, I don't like for the plate to sit just on six  nuts, The washers give the base a better footing and when you tighten up the top nuts, they don't dig into the paint. I just spent $360.- on powder coating the base and raising fixture that I like to keep them protected for a while. The nut by itself would dig into the plate as you tighten it, giving corrosion (rust) a chance. If everything was HD Galv. It would be OK but The bolts are made from F1554 grade 55 or A36 steel for strength. Hot dipped galvanized and stainless steel are softer and not recommended by tower manufacturers. That does not mean that they would not work but as you pointed out : It would be great in case of a failure to blame the manufacturer.  These days everyone likes to blame someone else!
An A36 is rated at 36,000 # per sq Inch yield strength and I think 65,000 # SQ " Tensile strength it has been a long time since I pulled them in our Steel Mill Lab. As the 1" bolt has a surface of 3.14 Sq" it will hold that much more before deforming or breaking.
I would nor worry too much about a failure but city planners & Lawyers etc would think differently. It's always good to CYA.
That is why I  called the manufacturer UST and ask about the washers.
I don't have a torque wrench either and tighten all nuts as tight as I can with the cheater pipe, double nut and check from time to time to insure that they don't loosen up. Once they are tight and you apply a good amount of paint, they will have a hard time to come loose!
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N7BMW
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« Reply #17 on: August 13, 2014, 09:54:41 PM »

N9RD your surface are of a 1 inch bolt is way off.  It is more like .78 inches - even less when you deduct the depth of the threads.  Formula is pi * R squared. 
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N9RD
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« Reply #18 on: August 14, 2014, 06:06:05 AM »

N9RD your surface are of a 1 inch bolt is way off.  It is more like .78 inches - even less when you deduct the depth of the threads.  Formula is pi * R squared. 

Thanks for pointing that out. You are absolutely right,I stand corrected!   Embarrassed it was late 
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WB6DGN
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« Reply #19 on: August 16, 2014, 07:37:23 PM »

Quote
N9RD your surface are of a 1 inch bolt is way off.  It is more like .78 inches - even less when you deduct the depth of the threads.  Formula is pi * R squared.

He was calculating the circumference of the bolt, not the area.  I missed that, too, until you pointed it out but it did seem way too large.
Tom
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N1CX
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« Reply #20 on: August 19, 2014, 03:49:56 PM »

Regular steel in a concrete base? YOUR NUTS. Rip the thing out and do it right. What a waste of money and time.

Why people can't do this stuff to spec always makes me shake my head. Glad it's not my tower.
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K1CJS
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« Reply #21 on: August 19, 2014, 05:43:25 PM »

...but The bolts are made from F1554 grade 55 or A36 steel for strength. Hot dipped galvanized and stainless steel are softer and not recommended by tower manufacturers. That does not mean that they would not work but as you pointed out : It would be great in case of a failure to blame the manufacturer.  These days everyone likes to blame someone else! ....

The point of the whole matter is simple.  It's YOUR tower, and if it were to come down, the tower manufacturer wouldn't be sued, YOU would.  And you would probably be found liable if you did not follow the tower manufacturer's instructions TO THE LETTER!  That's why some jurisdictions require plans and specifications that are signed off by a licensed engineer. 

It's not to give you extra bother or make your hobby/life miserable--IT'S TO PROTECT YOU!
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N4CR
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« Reply #22 on: August 20, 2014, 04:03:34 PM »

Split lock washers are counter indicated. By the time they can perform any locking action, the connection is loose. Well explained in this technical paper.

https://www.kimballmidwest.com/catalog/MarketingText/The%20Lock%20Washer%20By%20Guy%20Avellon.pdf

The lock mechanisms that work properly are NordLock, where any counterrotation causes the connection to tighten.

Double nutting is far preferable.

This is another very interesting paper:

https://www.kimballmidwest.com/catalog/MarketingText/A%20Fastener%20Primer%20-%20Stainless%20Steel%20By%20Guy%20Avellon.pdf
« Last Edit: August 20, 2014, 04:08:20 PM by N4CR » Logged

73 de N4CR, Phil

Never believe an atom. They make up everything.
AA4PB
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Posts: 12980




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« Reply #23 on: August 20, 2014, 06:04:04 PM »

I would think that double nutting would also increase the strength by having twice the thread contact area.
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WA8ZTZ
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« Reply #24 on: August 21, 2014, 10:39:16 AM »

If the manufacturer did not specify split lock washers, do not use them. 

In my experience, have seen a number of these fail (crack) in street lamp pole installations.
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WB4SPT
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Posts: 160




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« Reply #25 on: August 22, 2014, 09:42:40 AM »

Agree will all the negative split washer comments.  See my original post.  These 1" tower bolts are not going to have enough tensile loading or length to provide much stretch.  Ever wonder why most gas motors don't use ANY locking hardware on piston rod bolts?  They are under some of the most dramatic stress loading.  Just a single, non-locking type hex nut is used, no thread lock liquid, etc.
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NV2A
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« Reply #26 on: August 26, 2014, 03:58:08 PM »

For those concerned about my 1" thick Stainless "bolts".  I used the wrong term, they are 14" lag bolts made of 1" stainless.  My rerod cage has several circles of rerod tied to straight verticale pieces.  The circles contain the vertical long pieces.  My lag bolts are positioned inside the top circle to latch on to it.  My rebar work and stainless lag bolts came from a friend who does iron construction of large signs and those roofs over gas station islands.  Thiis is done to code in my neighborhood and I have every confidence in it.

For the record, I've never known stainless to be not as strong as steel.  I was a firearms engraver and believe Stainless in non-treated form about as tough a material there is to cut.  The chisels literally bounce back with each hammer blow where as 1045 and some of the other gun steels cut like butter.

Given all that, having a Rolls Royce type base to my tower, I still crank (winch) it down when the weather looks doubtful.  Why take a chance?
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WB4SPT
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« Reply #27 on: August 27, 2014, 10:24:45 AM »



For the record, I've never known stainless to be not as strong as steel.  I was a firearms engraver and believe Stainless in non-treated form about as tough a material there is to cut.  The chisels literally bounce back with each hammer blow where as 1045 and some of the other gun steels cut like butter.


Yep, SS is tough, however tensile strength is another matter.  300 series SS is around 84,000 psi, "ungraded" Grade 2 low carbon bolts are 74,000, Grade 5 is 120,000, Grade 8 close to 150,000.   All that said, you should be OK, but don't casually swap a graded bolt for SS;  It will be weaker. 
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WB6DGN
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« Reply #28 on: August 30, 2014, 11:00:16 PM »

Quote
For the record, I've never known stainless to be not as strong as steel.  I was a firearms engraver and believe Stainless in non-treated form about as tough a material there is to cut.

You're confusing hardness with strength.  NOT the same thing.  A couple examples of steel that makes stainless look like butter are 4130 steel and K-Monel.  There are others.  Also, stainless is brittle compared to most of the high-strength steels.  Cracking can be an issue, especially if vibration or working is part of its environment.  (From a long-retired race boat builder).
Tom
By the way, K-Monel is virtuallly stainless.  BUT, hold on to your wallet!
« Last Edit: August 30, 2014, 11:07:53 PM by WB6DGN » Logged
K8AXW
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« Reply #29 on: August 31, 2014, 06:39:15 AM »

They only other  thing I can offer this thread is to paint the bottom 16" of the tower with roofing cement, IF you have a male dog that likes to piss on anything vertical!   Roll Eyes
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