I used to watch the pipefitters at Todd Shipyards in Seattle bend coils
in steam pipes used to heat crude oil in the bottoms of tankers so it could
be pumped out. They did it at red heat over a mandrel in a gigantic lathe
and the pipe was fed through a holding device geared to the leadscrew so
they got the desired spiral pitch.

There is a concept in physics called "entropy". If when you spiralled a piece
of steel by hand, it naturally spirals equally along its whole length, this
would be IMHO a violation of the laws of entropy. That's like saying if you
chisel a line will it be straight.

Small bits of square stock are inexpensive. You can try your vise/wrench idea
for yourself. I think you'll become frustrated, however.

Grant Erwin

SteveB wrote:

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