On Thu, 23 Oct 2003 20:03:51 -0400, "BP" wrote:

However, it curved north soouth. Obviously I'm
confused about the direction the wheel stretches the metal.

It's a bit like a blacksmith's fuller or set hammer

If you strike with a flat-faced hammer, the metal spreads equally in
all directions. For drawing down metal in one direction alone, a
wedge-shaped fuller is used instead. There's spreading as you
describe, in an axis along the wedge (perpendicular to the face), but
negligibly so across the axis.

An English wheel is a wide wheel, so that it has this same wedging
action. If it's narrow (or if you put a narrow wheel in there), then
you get stretching in all directions, which is obviously less
controllable.


A second question also. What is it called and how do you do it - fold over
the edge of the sheet metal to form a rolled over edge that exposes a
rounded smooth surface?

Wired edges, rolled edges, or beaded edges.

Beaded edges are just a fold, and still rather narrow. To form a neat
one, fold the whole edge to 90° and then fold the whole lot down with
your softest mallet.

Wired edges are rolled around an internal wire, which is left in there
afterwards. Commonly seen on baker's loaf tins, the wire also
reinforces the corners. Start it on a round-edged stake, then work
over the wire with a mallet.

Rolled edges look like wired edges, but without the wire. You need a
roller swaging machine to form them, not a mallet.

--
Die Gotterspammerung - Junkmail of the Gods