Due to having a cold last weekend I did not make very much progress in the past 2 weeks until today. The 5" OD (4.870" ID) 6061-T6 tubing arrived and I trued the edges on my table saw using the fence and the mitre. The new length is 11.5 inches whereas the previous section was 8 inches. There is still several more hours work remaining on that piece.
The new control stick has become the most challenging portion of this project. Countless hours have gone into the best way to do this given my skills and available resources. I settled on welding (2) 1" x 1.5" x 1/8" tabs with a pair of #10 bolt holes to the spine of the truss. It was a major headache to weld these, but the penetration was good, however I won't earn any accolades on the appearance. There were some paint fumes and as a result found this job to be quite nauseating!
The control stick is 3/8" 4130 tube inserted through some 1/2" 4130 tubing (drilled). The pieces were squared and welded together. I used some 1/2" x 1" black UHMW polyethelene stock to make 2 pairs of guide blocks for the control stick. UHMW has low friction, almost as low as teflon, and high strength. The control stick has almost 0 play and will slide back under gravity to give you an idea as to how little friction there is. I will probably weld on a handle up top. I remembered to drill a hole into the 3/8" horizontal tube before welding in case I decide to run a push wire through the control stick. I still need to sort out the pulleys and guide blocks for the control cable, but so far it's moving forward. Lastly, the hammock/seat will need to be modified or remade. I want it to sit an additional 1" off the bottom to provide clearance for the sliding control stick.
