I was investigating getting a small mill and noticed that the
roller gap was between 4 and 6 mm. I'm confused. Is that correct?
That's the thickest piece you can fit between the rollers? If you
use 18 ga brass as a sandwich (.0403 in or 1.2 mm), you have less
than 2mm for your metal and pattern material. What am I missing?
The degree to which the rolls can be separated is determined by the
gears that drive them. Separate the rolls too much, and those gears
only barely contact each other, and instead of one roll (the one
driven by the crank) driving the other, they jam, or worse, if you
The main thing your missing is that rolling mills are designed as
their primary purpose, for making metal thinner. Their use in
producing roll printed pattern metal is very much secondary. Useful,
yes, but not their prime purpose.
Also, you’re missing that if your total thickness is limited, then
for heavens sake don’t sandwich your metal and pattern material with
such thick sheet. Go thinner.
also, you don’t really have to put the brass on both sides. Your
silver or metal to be patterned can serve as it’s own back side, if
it doesn’t have a pattern there already that you’re trying to
preserve. You only need to back the pattern side, and then only
really if you’re patterning your sheet with something that could
otherwise damage the rolls (like anything steel or similarly hard)
When I roll print, my favorite patterns are engine turned engraved
patterns (guiolloche engraving) which are engraved onto starret flat
ground tool steel stock. the back sides were finished to a finer
degree than the sheet as purchased, so their finish is equal to, or
better, than the finish on the rolls. And they are the full width of
the rolls. So I use nothing behind that. Their steel is at least a
little softer than the rolls, and pressure is evenly distrubuted
across the whole roll. In use, after a couple uses, the pattern sheet
curves too, so it’s a curvature about twice the radius of the roll
itself, which also makes patterning my metal easier. that metal, be
it silver or gold, does not need backing or sandwiching any more than
it would were I merely rolling it thinner, and the lack of a softer
metal back means pressure from the rolls is absorbed entirely by the
sheet being patterned, rather than also by the sandwich, so I get
good patterning without such extreme pressures anyway. When roll
printing other things for texture, whether I use a backing depends
on the material. with various papers, nothing seems needed. Sometimes
I’ll use another piece of silver or gold, so one on each side of the
paper or material, and get a pattern on both surfaces at the same
time (it’s a slightly different pattern, but still useful, if planned
bottom line, a rolling mill that opens to 6 mm, or even just 4mm,
should be quite enough to give you a lot of happy roll printing. But
remember. Larger diameter rolls also equal stiffer rolls, so more
pressure, enabling deeper better pattern developement or patterning
harder metal. So get the largest size rolling mill you can afford.
Also, the more expensive brands of mills, Durston, Cavalin, Dinkel,
are also more sturdy and better built. Last longer, work better.
Yes, they’re more money. But if you actually need a rolling mill at
all, buy the best you can manage. Higher quality tools are seldom a
poor choice, while less expensive ones sometimes turn out to be the
most expensive in the long run.