In the past I made this little unit to help me make a roll bar for my kit car.
Attachment 8467
It worked well in the end, I had inspiration from all over the net to make it and a few daft ideas that vibrated my hand to bits as well making the die.
A link to my web page that holds the information is here:-
Tube bender
http://www.locostbuilders.co.uk/gall...20test%201.jpg
Hope it gives someone an idea to make their own.
Adrian