While playing with my brand new rolling mill I have discovered a
tendency for it to dish the sterling silver I work in. For
instance, I tooka piece of 34 thou (I can’t get used to gauge,
sorry, it must be the engineer in me) sheet about 1.5 inch
square, annealed and rolled it down, gradually, to around 29
thou, rolling in both directions as I wanted a larger square. The
sheet already shows signs of buckling and thickness varies
between 30.5 and 29 thou - generally thinner at the edges, hence
the buckling.
The mill rolls appear perfect, I certainly can’t see any central
gap and feeler gauges report a constant gap across the rolls.
Should I be annealing more often or something else ? I suppose
the rolls could be deflecting under load but heck - what is a
mill for after all.
Andy Parker, Agate House Lapidary
Ulverston, Cumbria, England
Hi Andy…regarding your problem with the metal buckling in your
rolling mill: your rolling mill is probably fine - if you roll
the metal in one direction only (north/south, but not east/west)
the metal will not buckle. If you want to maintain the squareness
of your original piece of metal, you will have to roll in one
direction a few times, anneal and then change directions etc.
hi andy, you’re correct, there is nothing wrong with the mill. one
needs to anneal before changing direction, especially if that
direction is perpendicular to the previous pass. one can cheat a
little by inserting the metal at a 45 o angle to the previous
pass, but certainly no more than that
Regarding rolling metal, after all the latest posts it makes
sense about the buckling. Now my question - Will annealing the
piece after it has buckled flatten it or would you have to melt
it down and start over?
An easy tip: Place your annealed piece, distortions and all,
between two pieces of wood {a couple of chunks of 2x4 will do
nicely) and either pound them flat or stick them in a vise and
squeeze. You can re-anneal as often as you like until you have
it the way you want it…Donna
Lorri, After buckling, the metal is not destroyed and there is no
need to remelt it. Metal is the most forgiving of all materials.
Annealing and re-milling should remove the buckles, although not
necessarily in one pass. So if it is already the desired
thickness, re-milling it will reduce it and you will have to use
it for something else. Alan Revere