Large spool roller for RatRig VCore4

This is a mash up of the 608 bearing based spool roller that there are already many variations of. It is set up to feed out the back, so the rollers are recessed in the middle. It is still a work in progress because I have not finished printing the 4 kg roll. But based on the testing I have done and experience with other feeding systems this seems like it will work fine. If you try this setup and find a problem please post a comment.

Update V2: I changed the rollers to be concave instead of convex, and made the connection between the side frames and the base stiffer. The sides hold well with the dovetails and don't need any screws.

Update V4: The original design is narrow enough to fit between the print bed and the side of the printer, but can only accommodate 104 mm wide spools. The second model allows up to about 127 mm spools. Be careful with this because the spool is too wide to fit next to the print bed, so it limits the height of models that can be printed.

I have included the FreeCAD 1.1 dev model in case anyone wants to modify it. I found that the bearing dimensions had to be adjusted to get everything to fit. The bearing inside diameter (ID) and outside diameter (OD) can be adjusted in the VarSet parameters. Note that the clearance is subtracted/added from the values entered.

I used the TPU ECAS fitting that I have also posted. The ECAS doesn't lock the tube in place, but it does hold it pretty firmly so that the filament can be feed most of the way with one hand.

I printed this with PCTG and a brim for the roller only, no supports.