[TowerTalk] LM470 base dimensions

[Pete M]

I have 2 LM470's up currently and would NEVER consider welding the base 
up with out it attached to the tower ( or factory jig of some kind)..  I 
had my towers on my trailer and built the ground base with the pieces 
bolted to the tower base with spacer washers for extra clearance.  After 
being welded to keep positioning, I removed it and concreted these bases 
properly in the ground.  Heaven forbid you get something wrong with a 
4x4x7 concrete chunk in the ground.

Just my opinion.  BTW I am a certified welder.

Pete WA2ODO




On 10/20/2013 12:49 AM, K0DAN wrote:
> I don't think you will (or should) need washers with the base. If the 
> legs
> of the Tilt Assembly and tower are installed per specs there will be a
> little clearance between them, which you will need when you hoist the 
> tower
> to vertical. When you put the bolts (5/leg?) in, they will pull the steel
> together and you will have no need for washers, altho if you have room 
> for
> lockwashers, plus a couple stainless washers if you want to bond copper
> grounding to galvanized.
>
> In fact, when you're tilting the tower from horizontal to vertical,
> sometimes the alignments will not be as good as you planned or hoped for,
> and you will need to use a big pry bar (I use a truck tire iron), 
> drift pin,
> etc., and bring the legs & bolt holes into alignment by inserting &
> tightening one bolt at a time. I think that washers will just be another
> obstacle and complication. IIRC the towers I have been involved with have
> less than 1/4" spacing but I think with proper bolt installation they 
> will
> pull together,.
>
> I assume you have the current manual from BAMA? While things have 
> changed a
> bit from the older to newer towers, the basics are essentially unchanged.
>
> There are drawings of the footings which show the rebar cage, tower, 
> etc., these should give you the construction details you need.
>
> GL es 73
>
> dan
> k0dan
>
>
>
> -----Original Message----- From: Roger (K8RI) on TT
> Sent: October 19, 2013 19:30
> To: towertalk at contesting.com
> Subject: [TowerTalk] LM470 base dimensions
>
>
> 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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