Well, the aluminum tower that fell into my lap a few weeks ago now checks out structurally. After a few minor repairs, that is. Mechanically, however, it was a different story. The entire pulley system had to be re-worked, but it wasn't a big issue and I got it done. The tower itself did not come with a tower base that was conducive to mounting on concrete. At least not a design I was willing to respect, in any case. Since the tower is aluminum construction, I 'could' use steel for the base, but over time steel will create an undesirable electrolytic reaction between the steel base and the tower, so I'm not inclined to use steel. But alas, I had some scrap 3/8" aluminum laying around and am making the mounting flange from that stock instead. Here are some pics of the beginnings. Cutting the base out with the plasma cutter. I need more Argon before I start welding up the supports, but it'll be coming along shortly.