I. Like. It!!!
I’ve been a bit reluctant to pursue the “floating rails” thing because it adds a bit of complexity to levelling since there are three surfaces to get parallel not just one.
However I’ve just realised that it may serve well in keeping the dust away from the wheels.
Is that a reasonable thought?
I think, in this case, because of the CNC method of cutting this for assembly, having the surfaces parallel should not be an issue. I do also think there could be some benefit regarding keeping some dust/chips away from wheels.
Just two, the middle in this case will always be surfaced since you can cut off the edge.
It could keep stuff away from the bearings, there is a gap, or a step. I have never had an issue with that though. This last round of HDPE was the most messy thing I have cut, a few chips get near the bearings but for the most part my Z was not critical to that degree, if it was I would either put a brush there or a longer tape skirt on the dust shoe. I know this seems to bother a lot of people, I just don’t see it as a common issue. Worst case is cutting right next to the bearings. At that point what is the biggest chip your machine throws and how far off could it possibly move the Z? Big stuff gets pushed out of the way. At the other end there is some trig involved but basically zero effect of a chip under the wheels.
I made that design that way for different thickness materials, and hopefully slide the vac hose on the rails side gap.
I would think the twist of the table (making rails not parallel) would be the only degree of freedom, and there would need to be a procedure to true the table in any case.
Parhaps shim the feet until the rails are parallel. Use the cnc to surface the top of the ribs. Attach top and bottom skins to make the table super stiff.