Where are you getting your terminology from? Nook calls a fixed and a rigidly mounted end, allowing no rotation.In fixity terms is it SIMPLE-SIMPLE or SIMPLE-FIXED? The fixed end seems to be nothing more than two bearings spaced twice the diameter of the drive screw apart. Is that overkill for a JGRO?
Basically, yes. But it's more common to use two bearings, one on each side of a fixed mount. This is because angular contact and tapered roller bearings can only handle thrust in one direction, so two bearings are needed.For keeping the screw from loading the motor bearings it seems like you need a nut-spacer-bearing-spacer-nut combination. The nuts are fixed to the screws and 'capture' the bearing. So, as long as the motor and the bearing are attached to fixed members of the frame they can't move relative to each other. Is this the right idea?
Actually, they are to deal with axial loads. Which are loads along the length of the screw.but there always seems to be variations: thrust bearings, angular thrust bearings, etc. I'm guessing that is to deal with non-axial loads placed on the screw?
This .pdf has some exploded views that show the proper (but very expensive) way to do it. http://www.nookindustries.com/pdf/NookEndsmounts.pdf
Loads on a JGRO and similar are rather light, and you can actually get away with using skate bearings instead of angular contact bearings. This is how I did mine (not a JGRO, though) http://www.cnczone.com/forums/diy-cn...s_without.html
Be aware that you can't use the nut - bearing - bearing - nut method on a multi start screws, as multi start acme nuts won't tighten. So most people use some type of clamp on each side of the bearings.
This image uses needle bearings, which can't handle radial loads, so the additional radial bearing is needed.
Notice the clamp on collar which holds everything tight to the bearing block.