that works, I did make one with a set of mole grips and exhaust clamp would be ok for ali tube not stainless.I made a manual one for putting a bead on a bit of alloy that needed to be about 100mm from the end of the tube.
Looked a bit like this
View attachment 294523
Clamp the flat bit at the bottom in a vice.
It was 10x20 flat bar or something like that.
8mm bolt for the pivot, cut down drill bit shank for the former.
Some more holes for a depth stop and hit the end with a hammer whole turning the tube.
It was surprising how well it worked.
I did think about adding an air chisel to power it but never got that far
View attachment 294522
that works, I did make one with a set of mole grips and exhaust clamp would be ok for ali tube not stainless.
I like that one, I am sure I have bits of scrap to make something similar, is that a valve spring I spy