As I mentioned before, I wasn't able to locate tubing that was exactly what I needed, so I had to bore out the 0.624" ID tubing to close to the right size. I had a little bit of time this evening, so I faced and drilled out the tubing to 47/64ths (just under the final 3/4" size). Later I'll ream it to 0.75" and run a hone through it to clean up the surface.
You can see a decent amount of material was removed.
Since I didn't have an +8" long drill bit, I had to drill the tube from both ends. If you look closely, you can see a slight step in the middle. That will come out when the tubes get reamed and honed later.
Short video clip.
d.wilson mfg works on interesting projects from time to time, so this is the place we'll share some of them.