On Sun, 17 Sep 2006 07:52:47 -0700, in rec.crafts.jewelry Abrasha
wrote:

br wrote:
I doubt that "wobbles and bends" would be a big problem as the disks
will be hand-punched.

You may not have trouble because of "wobbles and bends" but you'll have plenty
of other problems. You better have a damn good punch for that, because if you
don't you are going to have a hell of a time punching circles out of .1 mm thick
sheet. That is not even sheet anymore, but almost foil. If you punch is not
made to a very tight tolerance, you will drag the sheet into the punch and you
will not get a clean cut. I have circle cutters, that have decent tolerances,
and I cannot cut anything very clean that is thinner than .3 mm. For larger
circles I make my own punches, that cut just fine. I leave them unhardened,
because it doesn't really matter for gold, if they are hard or not, and I do not
have to cut thousands of circles.

True again, that most circle punchs are intended for thicker metal, and have a
bit more clearance between punch and die for that application.

I've used ordinary light weight paper punches with foil. they work well. There
are a wide range of odd and interesting shapes available in the "crafts" stores
for people and kids doing scrapbooks and similar home projects that use paper
punches. The things are cheap. Not sure they'll hold up to thousands of holes
in metal, but at less than ten bucks each, buy another punch when it starts to
get dull.

Or, rather than the punches that use a punch and die, use the single type of
punch used for shim stock, leather, etc. Some are called arch punches, and have
a full hollow center inside the sharpened cutting edge with a side cutout to
retrieve cut parts. Others are like the cheap cutters sold alongside dapping
punches from india. Either, used against a firm cutting surface like a copper
sheet, might work well enough with gold foil. You might want to anneal it for
this type of punch.

Am I correct in assuming that the "straightness" of
the ribbon depends on the parallelism of the two rollers? Concerning a
polished surface (only one side needs to be polished); would it be feasible
to use a long strip of highly polished spring steel, run through the mill at
the same time as the gold ribbon, to polish the surface?

That is the single best way to destroy your rolling mill in short order! (Well,
maybe not neutralizing your sheet well from acid after pickling is a better way)

If I'd see you do that in my shop, I'd kick you out the door faster than you can
say "Oh ****!" I have seen idiots doing stuff like that with bunched up steel
wire to create an "interesting" rolled pattern on sheet. They ended up with the
patterns in the gold and silver, as well as on the rolls!

I worked for some time, years ago, in a small two person (including me) shop in
Detroit, located in an office building with lots of other jewelers, many of whom
were of middle eastern origin. Big families, and sometimes they'd bring their
kids to hang around the building too. Nice kids. Well, my boss was a nice good
looking blonde lady whom these kids adored. So we'd now and then have these
kids hanging around our shop when they were bored, and Mary Jo sometimes woiuld
let them amuse themselves by rolling down pennies in the mill. One time,
apparently, shortly before I got there, and shortly after she'd just purchased a
nice new rolling mill, she'd given a kid a penny to roll down, and then was
distracted by answering the phone. The did finished the penny, and looked for
something else cool to flatten. Came up with some used jewelers saw blades and
a couple #12 scalpel blades for cutting rubber molds. As Mary Jo got off the
phone, he asked her dejectedly why these cool things hadn't also gotten long and
flat? I'm glad I wasn't there to see her reaction. Apparently, she didn't
actually kill the kid, but it was close. It was a combination mill, so we
couldn't even get the rolls reground or it would have messed up the wire
grooves. So for years, I had to just avoid that part of the rolls with the
sawblade and scalpel blade imprints, which fortunately, was right along an edge
of the roll.

On the other hand, I often do pretty much this same thing to produce an embossed
pattern on the metal. I like to use engine turned (guilloche) patterns on some
of my work, and have the machine to do so. But for some less costly work, the
time required to actually cut a real guilloche pattern on the metal isn't
warranted. So I cut that pattern on a three inch wide sheet of starret flat
ground stock that I'd polished on one side (the side I cut), and had had
reground on the other to a surface finish slightly better than the surface of an
OLD somewhat beat up flat mill I've got, with three inch wide rolls. I roll
print my metal with that sandwich. The reason this works is that the steel
sheet has a better surface than the mill, so it doesn't make it worse, and it's
the full width of the mill, distributing pressure, and is curved as well, though
to a wider arc than the mill rolls, but again distributing pressure. And it's
not hardened. This works fine. The metal takes a fine impression from the
sheet, and the mill is not damaged. In use, it's very important that the
embossing steel sheet is longer and wider than the piece being embossed, so that
as the gold or silver finishes up, and exits the mill, the embossing tool is
still there in full contact with the mill. Now, though, with the gold gone, the
pressure on the mill is off, so the ending (or at the beginning starting) edge
of the embossing tool does not cause a mark on the mill.

In short, you CAN do this, IF you think it through carefully and understand that
doing it wrong will destroy your rolls.

But for simply polishing the metal during rolling, having the rolls themselves
polished would be easier perhaps. Just be sure the place doing it understands
that the rolls MUST remain highly concentric and cylindrical. This is not as
easy as it sounds. It's high precision machining, and likely to cost some
money, if you want the resulting rolls to be able to process metal as thin as
the foil you wish.

Peter