The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1883-02-03

long, anu ABOUT lncueS "luo; anu lioih 2
to { of an inch in thickness, rolled accord
ing to the plates required at so many
pounds per foot. 1t is cut in what may be
termed a jack-in-the-box or steam shear,
say about 10 pounds to a piece which will
eventually be rolled into 16 sheets of 20
inches long by II inches wide, 112 of such
sheets forming box, and weighing when
timed nearly l cwt.
This piece of iron is first placed in a re-
verberatory furnace, heated to redness, put
through the chilled rolls, and rolled in what
is termed thick, five times; reheated and
rolled in singles twice; doubled, reheated
and rolled three times; doubled, reheated
and rolled twice; doubled, reheated and
rolled in eights, twice, until they are stretch
ed out to the required thickness. The
length of the bar exceeds by about one inch
the width of the sheet to be made, so as to
allow for the shearing process, and the bar
is therefore rolled with its axis parallel to
that of the rolls. Great attention is ne
cessary in the construction and manage
ment of the mill furnaces, so that the heat
ing of the bar and sheets for rolling may
be effected with the utmost regularity, and
without the formation of scale on the sur
face of the bars or sheets; for when scaling
takes place from the draugh in the furnace
being too keen or the heat raised too high
the quality of the iron is injured; the scale,
if subsequently rolled into the iron, leaves
rough surface on the plates in the after pro-
cess of separating and picking. The plates
are then sheared, and the rough edges taken
off. The iron of 10 pounds or therea-
bouts makes Is sheets which, being cut in
half, leaves 8 sheets in piece closely
wedged. Girls with small iron hatchets open
them They are then termed black-plate.
From one ton of bar iron about 164 cwt.
of black-plate is made; the loss is termed
shearings, and is worked up again in the
forge-fneries. The plates are next sent to
be picked, i. e., immersed in heated dilute
sulphuric acid, known as oil of vitriol.
This process is done by aid of a patent,
known as Hutchings' patent picking ma
chine The plates are placed in a brass
cradle or receptacle, lifted by hydraulic,
then dropped down into round wooden
or lead tank containing the o. v. the era
die is then made to revolve by means of
steam power, to enable the liquid to rush
between the sheets, which revolution is re-
tanned. They are lifted again by the hy-
draulic, and dropped into a tub, little
apart from the last, containing water only,
the cradle revolving as in last tub, so that
the water may rush between the sheets to
cleanse or wash away all traces of the acid,
when taken up again the plates are clean
and bright as silver. They are next sub
jected to bright red heat, which lasts
from II to "a hours, in closed iron anneal-
ing pots in reverberatory furnace; they are
we'll covered on the top to prevent the plates
from being burnt the heat is kept as high
as it can be without softening them to such
degree as to cause them to stick fast to-
gether and prevent their separation when
cold.
They next pass simply through cold
rolls, three, four, or more times, as may be
deemed requisite. These rolls are highly
polished, and must be set in accurate order
to give the plates perfectly fiat set and
well polished surface. Again they are an
nealed or softened at a lower temperature
than the first, as their surfaces would be
damaged by being in any degree stuck to-
gether. Picked again as before excepting
that the liquid is considerably weaker than
previously, placed in cast iron troughs con-
tanning clean water renewed by stream
constantly flowing through, they are then
taken in hand singly, and secured if nee
essary with sand and hempen pads before
being delivered to the tinman.
Now comes the last process. The sheets
are iron only SO far. They next reach the
tin house, and are placed in trough con-
tanning clean water, ready for the tinman,
as he is termed, who then picks them up
and puts them singly in grease pan con-
tanning palm oil, to soak, and after being
there for short time the tinman places
the sheets in large iron pot containing
molten tin, with covering of palm oil
Here it unites with the tin, to which it has
strong affinity. When he has performed
his part the plates are handed over to the
next man, called a washman, whose pot
contains pure molten tin; after they have
soaked in his pot little, he raises them
with tongs on to the hob as he requires
them, brushes the surface of both sides Of
each sheet, and after dipping them into
another pot containing molten tin again
they are sent through rolls which work in
large pot containing palm oil, and the
speed at which the rolls move regulates the
quantity of tin to be put on each sheet
They are afterward raised from the rolk
(under which they have been passing) BY
youth, called raiser, handed to two
young women, who rub them in bins Oh
boxes containing bran, one after the other
which takes off the grease; another girl
called duster, gives them further polish