Yesterday I improved my own knock down base with my suggestion proposed in post 30 of this thread.
I am really pleased with the increased rigidity it provides, as evidenced by the elimination of the slight slop I previously felt when reversing the azimuth direction while tracking. In this case I angled the bolts only 10 degrees to match the edge of the panel that the hexagonal tube just cleared.
First I turned a couple of plastic knobs 3/4" diameter x 1 1/8" long by screwing them onto a 1/4-20 bolt whose head I had removed so that it fit into a router collet on my wood lathe. A couple of wide files produced the shape in short order, and a chainsaw file was used to make flutes by hand every 45 degrees that were easy to grip with fingertips. (These flutes were inspired by one of my favorite screwdrivers). I then made a new rear panel for my rocker box that was slightly larger than the original (which the tube had cleared by 3/8"), bored 9/32" holes from the ends, and made my access holes using a scrollsaw.
Note that in the above photo I also sharpened the bolt that had been used to chuck the knob in the lathe to make a transfer punch for the side panels. The access hole is 3/4" longer than the assembly of the knob, star lock washer, nut, and flat washer (that were used in the final assembly) combined.
Making the mating holes for the T-nuts required a bit of care, but I managed to hide the T-nut under the original reinforcement plate the original latch had been screwed to on the outside of the rocker box. The only reason I didn't angle the bolts higher to take advantage of a higher attach point and improved angle for the forces was that I was targeting the original latch location for aesthetics. I didn't want the rocker box to look reworked or to have visible T-nuts (gasp!). I adjusted the jam nuts on the bolts so that I had good pressure of the flat washer against side of the access hole without quite bottoming out against that reinforcement plate.
Assembly is very rigid, and also makes the stiffness of the fold-out diagonal reinforcements on the sides of the rocker box more apparent. It does take about thirty more seconds to put together than the latches had, but I don't mind. In the end I verified that I indeed had the 1/8" clearance to the tube I had expected. I'm getting close to painting and varnishing this project!
Edited by jtsenghas, 25 January 2015 - 06:46 PM.