Now, please forgive some ignorant questions. I can't really see the twisting tools very well. It sounds like you made grooves in the tube and then twisted? Can you go into more detail on the process? Thanks!
I want to you guys to think too Everything is made so easy nowadays with the google and all
It's basically a thread die, a very dull one. Drill a hole that has two angles. One angle is for the angle that the bearing is against the copper and other for how fast it moves when you roll it on the tube. I'll took a video clip next time I'm doing something (may take some time as I'm totally out of money. I've to wait until the scrapyard has some copper...)
I don't know how the real tools work, but I would guess the process is the same. I don't think that the tube is actually twisted at all, just "grooved".