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Re: [TowerTalk] Failed HDX572 Raising fixture Leg and base

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Failed HDX572 Raising fixture Leg and base
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Sun, 9 Aug 2015 18:27:47 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
That one photo shows all the characteristics of a poor weld. There is actually rust behind the weld and the surface of the weld is flat. The weld separated from the underlying metal. There was virtually no penetration, the sign of insufficient temperature/current.

Typically the piece has the bottom where the weld is located, ground at a 45 degree angle so the weld penetrates more area of both pieces, but a good weld can be made without grinding.

They taught that in "Farm Shop", 60 years ago where the only welding was stick, or torch.


73

Roger (K8RI)


On 8/9/2015 5:24 PM, Robert Harmon wrote:
Rich,

In my opinion it separated because the weld did not have full penetration.  Not 
enough amperage when the weld was made.
One of the first welds learned in welding class is a fillet weld where a piece 
of steel plate is welded to another at right angle.
After running a fillet weld on one side, it is clamped in a vice and hit with a 
hammer on the side opposite the fillet.  If it breaks off
you did not have the amperage high enough for good penetration.  The pictures 
show this to me.  If welded correctly with full penetration
the joint is stronger than the metal and we would see tearing of the metal, and 
in this case no rust where it tore off.

Bob
K6UJ


On Aug 9, 2015, at 12:19 PM, Rich Hallman - N7TR <rich@n7tr.com> wrote:

This morning I was lowering my HDX572 and as it was almost down one of the base 
ears that the raising fixture leg mounts to failed.   Fortunately it was a slow 
drop and the tower is still ok.  If it failed while it was higher this could 
have been a different story.

I will need a new raising fixture and a new HDX572 base.   I have a like new 
spare TRX-80HD raising fixture for my HDX589 so I should be ok there.

I posted some pics and will add more later today.  From the looks of the break, 
I am seeing rust (Not clean metal) where the welds were.  Also I'm not sure if 
the ear on the one leg that mounts to the raising fixture began to bend first 
or not.   But it is bent a hard 90 degrees now as you can see.

Anyone else see something like this in the past?   This is an older US Tower so 
I'm not sure if the bases are built better now or not for the mounting ear.

Go to my QRZ Page http://www.qrz.com/db/N7TR  And look for the link called 
HDX572 Raising Fixture Failure.

Rich N7TR
ex KI3V, N3AMK, WB3JOV
www.n7tr.com<http://www.n7tr.com>
http://www.qrz.com/db/N7TR
Telnet: dxc.n7tr.com N7TR DXCluster


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--

73

Roger (K8RI)


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