it warps anything I pass through it, despite calibrating the
rollers all the time.
There are two (or more) flavors of the way metal warps in a rolling
mill. If the rolls are not flat, usually where the center of one or
both rolls is worn, so the centerline of the metal isn’t rolled as
thin as closer to the edges, then you’re right. It’s messed up, or at
least, could benefit from having the rolls trued by a machine shop.
Or save that mill for roll printing. Metal put through that sort of
mill will warp in multiple directions as the edges get stretched
more than the middle. can almost look like frilled edges.
However, another type of warping happens with even good mills. There
are often slight differences in an ingot from one spot to another,
plus, while rolling, the surfaces tend to stretch more than the
interior of the ingot, at least initially until it’s been rolled down
far enough for internal stresses to equalize. Before that happens,
the metal will often leave the mill curved in the same directions the
rolls curve, or may wave up and down. The key here is that side to
side the metal remains at least mostly flat and unform. The waves are
in one plane only.
if you keep rolling that thinner, eventually internal stress evens
out and the sheet will again become mostly flat. Prior to that, you
can anneal and flatten with a mallet. This type of warping/curving is
related mostly to uneven ingots, or to very slight but normal
variances in roll parallelism, as well as being more pronounced with
smaller diameter rolls. Buying a better rolling mill will help all
this, but will not eliminate all of the wavyness. If you expect to
take annealed sheet or an ingot and roll it down and have it come out
of the mill dead flat, just like it went in, every time, you’re going
to be very disappointed.
Mills that come close to that are going to be more in the range of
industrial sized rolling mills, with much larger diameter rolls than
seen on jewelers mills.