More rigid central carriage

Hi guys,

I was wondering if, in your opinion, there would be any issue I didn’t thought of about making the central carriage in one single piece, or at least a few pieces stacked in layers, like a sandwich.

On my machine, the only rigidity issue I have seems to come from the carriage, so I would like to redesign it in order to mill aluminum at reasonable speeds with acceptable results. Seems like the bearing have a little play, no matter how tight they are and even if they all make contact on the tubes, the entire assembly can flex. It is not that much, maybe one millimeter of deflexion at the bit or less, but I’m pretty sure it could be reduced just by having a different carriage and different bearings. I have no noticeable deflexion of my tubes since the ones I use are made of a tough material, so it is not my limitation so far (it may very well be on your machines though).

I plan to use these kind of bearings, instead of the current ones:

I think this cannot be used for the Z axis, since it has to stay opened at least on one side to attach the tool mount, but it would at least be used to link the X and Y axis together.

Do you have any thought, suggestions, warnings or recommendations before I try? Any advice would be appreciated, I’m pretty sure it will work but several brains are often better than a single one!

I’ll start to work on the 3D design this week.