thanks mate,
i used a couple of different ways to make them
the first way, see post #108 , slot the pipe then hammer/dolly the pipe over a solid bit of steel rod.
the end that will end up narrow, can also be clamped in a vice and carefully closed up, then dollied up.
the second way, is the just cut a v section out of your pipe (smaller than what you need)
then work on closing the big gap up at the end.
once it is pretty close then it is just a matter of a final trim up to make the 2 edges butt up perfect, and weld it together.
having 1 weld/join down the length of the pipe is easier to hide.
put the join at the bottom