[TowerTalk] LM470 base dimensions
EZRhino at fastmovers.biz
Sat Oct 19 20:55:17 EDT 2013
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.
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)
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