[member=48572]Shane Holland[/member] - thanks for the reply. If I follow your suggestions correctly, I still cannot get close to 46". Using 18mm ply, the Off-side (non-pivot) rail support is raised just enough above the MFT/3 surface to limit the workable width of the piece to be slid under the rail to far less than 46" wide. Moreover, the 1080 rail is only 42 1/2" long, less space to mount to the pivot support, again limiting cross cut ability to something less than 42". The useable work-surface of the MFT/3, without fence or rail supports is approx. 28 1/4" wide by 43 3/8" long. Perhaps a sketch would help see what I am missing.
[member=9136]CarolinaNomad[/member] - you are approaching the issue the as I have found to be the more "do-able." Using a 1900 rail, mounted across the length of the MFT/3, with all adjustments made to ensure there is NO flex in the fence, rail is properly supported, etc., get me to my earlier post of approx. 40" cross cut capacity, BUT, practically, that is not a set-up which I find suitable for precise work - which means my cross-cut capacity is max'ed out at about 36".
Thus, my real issue now becomes using the 1900 rail. Given the MFT/3 is about 3' off the floor, the rail is, when mounted to the pivot support, approx. 6' long, means I hit my shop lights when trying to get the rail up and out of the way - my shop ceiling is 9' less the shop lights which drop down some 9".
In spite of the obvious math and dimensional limitations, I always hope there are ways that work outside my limited approach.
Thanks Shane, thanks Carolina Nomad for your time and suggestions, I'm back in the shop trying to rearrange things.
Don