J4 Main Shaft Construction

I'm building the AR3 that will use the Teensy 4.1 and the AR4 software and inexpensively as possible but not totally 3D printed.
Buying the J4 Main Shaft as a long piece of stock aluminum was too expensive. Then I stumbled on some folding lawn chairs that used 1" OD aluminum tube. Problem is that it's really thin wall and likely even just trying to drill it may compress it out of round. As it is it turns nicely in the bearings and the rest of the parts are all a friction fit onto it.
So what to do? Easy. 3D print an inner liner that is a slip fit into the tube and has a 12.7mm hole down the middle for the joint lead screw. I'll epoxy it in place and then I can easily hold it and drill/tap the 3 holes.