I want to spiral some small square stock. Probably 1/4" and 3/8" dimension.
What is the easiest practical way to do this? Hold one end in a vise and
twist the other with a crescent? How do I keep the whole thing straight, or
do I straighten it later? I want to spiral sections along a longer piece
rather than spiral the whole length.

And when I do want to spiral the whole length, will it spiral equally along
the length?

Steve