Mark wrote:
> Stephen if you can find the article I would appreciate the reference or
> possibly getting a xerox.

I think it is the one that was just referred to on the list as the
standard article on slitting mills. If I can find it I'll confirm.

> Your comment on the iron used for drawing is very much to the point.  I am
> having great difficulty finding out what made "drawing iron" special and how
> to tell if a sample meets the required characteristics, purity?,
> distribution or percentage of slag? etc.
> ...
> viewed from the point of view of the medieval smith.  How did he know his
> bar of iron was now at a point that was suitable for wire drawing.

"Wrought iron" has been referred to several times in this thread. Is this
perhaps a more general usage of the term ? I thought wrought iron meant
specifically the slaggy-fibrous specific raw iron material which we are
all familiar with from industrial products (at least prior to the 1960s),
and which is definitely not suitable for wire-drawing. Anyway, maybe the
usage here is intended to mean bloomery iron raw material, which would be
closer to what is required for wire drawing. As was discovered rather
quickly at Tintern you can't use just any iron for this, however. Schubert
describes the processes in his book, and I have a bunch of articles on it
which I can mention if there's interest. There were (are) two requirements
for iron wire...completely decarburized and high phosphorus content, both
of which were achieved by using the first material to melt of the bloom,
collecting it on a staff, then passing it through the fire frequently.
Martha Goodway has done work on this topic - if she's still on list she
may comment. I am just now beginning work on a project to duplicate the
raw material and study the mechanical properties of the wire as a function
of drawing parameters...but that's not underway yet.

Stephen

Stephen Birkett Fortepianos
Authentic Reproductions of 18th and 19th Century Pianos
464 Winchester Drive
Waterloo, Ontario
Canada N2T 1K5
tel: 519-885-2228
mailto: [log in to unmask]