On Wed, 20 Sep 2006 01:43:19 -0700, in rec.crafts.jewelry ted frater
wrote:


OK folks,
Here are the results.
Let the professional craftsfolk here and more importantly potential
customers draw their own conclusions who writes the most bull/s.

Careful how you define that, Ted :-)

The thing that bothers me, and perhaps Abrasha too, is that you've still not
tested the problem that the original poster brought up. That is how much WIRE
spreads out when rolled.

As has been pointed out, by me, by abrasha, and perhaps others, the diameter of
the rolls makes a difference. smaller diameter rolls spread the wire less, with
the same percentage reduction per pass. Because you've chosen to make this
"test" with quarter inch rod, instead of the 1.2 mm wire that the whole thread
was actually discussing, you're actually not testing the original question, but
rather, nicely demonstrating the truth of the statement that rolls diameter
matters, since you're using a rolls that, compared to the size of the "wire"
being rolled, is about a tenth the diameter of what the situation would be if
the same rolls were used to roll that wire instead of your heavy copper rod.
Also, don't expect copper to give exactly the same degree of spreading as will
gold. it starts softer, and work hardens more slowly. This affects the degree
of lateral spreading too. (It's about the degree to which lateral forces are
exceeding the elastic limit of the metal in relation to how the longitudinal
forces are doing the same, as well as the tensile strength and springiness of
the metal resisting or springing back from lateral stresses instead of
permenantly spreading out. )

So, now try the real test. Start with the actual discussed wire size, 1.2 mm
round, in annealed 18K yellow gold. You need not work with much. An inch long
will do fine.. Roll that down to the specified foil thickness. See what the
width is then

1/4in pure copper rod 5&3/4in long fully annealed rolled to 30/1000 in
thick went to 29in long.
width went from .25in to .30in.
thats a 50/1000in increase. 50/1000 in into .25in is a 20% increase
in width.

then I took a .50in wide by 3/16ths in thick by 6 &1/4in long copper
strip fully annealed.
This went to 32in at 30/1000in thick
and went from .5in to .553in wide.
I make that a 10%increase in width to all intents and purposes as
makes no odds..

so my experience of 2in wide is about right. when previously I said
a width increase of 2 to 4% depending on material.


No one has significantly disagreed with your estimate as it applies to rolling
down strips of wider sheet metal instead of bar stock or wire. Your own figures
here show that the bar stock spread out twice as much as your strip which was
twice the width and started considerably thinner. The disagreement is in
extrapolating the same degree of lateral spreading to wire stock, as you
experience with this plate stock. As you'll find if you try it, that doesn't
quite work.

This test:-
Annealing time 10 mins total
rolling time 10 mins total.
Writing time and measuring 30 mins.
Bull/s time nill.

Have a nice day, dont you say?
Ted

Thanks. I will.

You too!

Peter