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Re: [TowerTalk] LM470 base dimensions

To: Roger (K8RI) on TT <K8RI-on-TowerTalk@tm.net>
Subject: Re: [TowerTalk] LM470 base dimensions
From: EZ Rhino <EZRhino@fastmovers.biz>
Date: Sat, 19 Oct 2013 18:55:17 -0600
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Hi Roger,

When I built my base I used the tower itself as the template for the ears.  I 
would highly recommend doing this or you be sorry when you try to put the two 
together.  Keep reading.  I bolted the ears to the tower and then tack welded 
the ears to the base with the tower laying horizontal.  I used some 16 gauge 
sheetmetal (1/16") as spacers so the ears were slightly apart when the base was 
taken off the tower.  Don't forget to also do a similar spacer for the third 
ear!  The problem I ran into, and if I did it over I could remedy this problem, 
was that when I started welding the ears moved from the heat.  A LOT!  Remember 
we're talking 1/2" steel here (in my case, anyways) and that requires a hell of 
a lot of welder to do it properly.  To avoid the warpage, I would 
cross/diagonally brace the crud out of the ears so they can not move at all.  
Then cut off the braces when it is all welded.  I welded the ears on with three 
passes, and the rest of the gussets with single passes on 
 both sides.  The final product weighs in about 225 pounds.  I think the base 
itself can hold up the tower without the concrete, lol.

I finally got my tower up today (hoorah!) and it only required a small amount 
of prying with a pointy prybar to align the holes enough to get all 15 bolts 
in.  This was less prying/hammering/cursing than I've seen on other factory UST 
 baseplates, so I felt good about the way things fit.  (I cut out the holes and 
all the baseplate pieces on a buddy's plasma table, so all holes were right on 
the money).  I used a homebuilt raising fixture made from 4x4 posts and a 
Fulton 2500 winch leftover from another tower project.  

Chris
KF7P






On Oct 19, 2013, at 18:30 , Roger (K8RI) on TT wrote:


I'm getting ready to do the final welds on the base.  Unfortunatel there are no 
specific dimensions given in the paperwork.

The outside distance on the tower "ears" is 23".  I'm using the raising fixture 
to hold the base "ears" for building the rebar cage.  When bolted to the 
raising fixture the "inside" dimension between the ears is 23 1/4" That leaves 
an 1/8th of an inch space between the tower ears and the base ears on each side 
, or 1/4" total.

I'm assuming I should space the base ears in from the raising fixture with 
washers, to give no more than 1/32nd of an inch clearance so when the bolts are 
tight the tower and base ears will mate flush and tight..  This should allow 
for a snug fit, but not interfere with raising the tower and give face to face 
contact for a good holding force when the bolts are tight ( snug plus 1/2 turn)

Comments?

73

Roger (K8RI)

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