CLOSER AND CLOSER.......
Spent some more time on the seatrail conundrum and working on a better way to hang the inside rail while still staying out of the center tunnel and transfercase areas.
The best solution was to build an offset seatrail mount so that the inside rail could land in a more realistic spot (on the transverse tubes) and leave enough room for a sheetmetal cover for the transmission / transfercase tunnel.
One problem with the idea is that the seat cushion does not stay in the same place when someone is actually sitting in the seat. That cushion is displaced downward by at least an inch, so if the new seat track mount was run parallel to the first one (but 4" more inboarded) the passenger would totally feel that bar through the foam while seated. (Kind of like that awful metal bar that is under the mattresses in a fold-out couch!)
So, the idea was to find a way to support that rail strongly, but to stay out of the seating area as much as possible. Going with a diagonal bar allows the "butt" area of the seat to be unobstructed, and moves the bar closer to the knees where there would be a lot lower concentration of weight... so the odds of feeling unusual lumps from above should be minimal.
Here you can see the effect of moving the seatrail inboard, and how that diagonal bar provides a landing spot for that one bolt location that needs it.
When mounted back into the truck, the effect is much nicer than before. There is LOTS of extra clearance now between the seat track and the Atlas box ( I guess the term "LOTS" is all relative!) so there will enough room for sheetmetal enclosures to start closing off the interior bits from the underneath bits.
With a final design for the rear mounts, it was possible to take more accurate measurements directly off the seat and locate it's position relative to the outer rollcage bars and the transverse bars... and design a new forward-pivot setup to allow the seat to move forward AND tilt (if desired) to really maximize the space behind the seat for ingress / egress.
Now it's off to locate some bronze shoulder-bolts (oops! I meant bushings) to make up durable and smooth pivots... then some fabrication for mounting tabs and front "shackle" mounts to render this drawing in mild-steel.
-G