The Afro-American. [volume] (Baltimore, Md.) 1892-1899, 1895-12-14


futsres Fia Esfocsnz w IL Il w i i sss
dera Have Heeh Able To Masters
The operation of casting d bell Is q
most Interesting one. The flask where
on and wherein the mold Is maie con-
sisfs Of tgyo parts, CONSTRUCTED al boiler
iron, Of . general bell FORM ,bIenti-
fully perforated with holes for escap-
Ing gas while casting, one being SO
much less II Size than its fellow as to
give space for the loan forming the
mold between the two. No pattern"
as the term is generally used, ls pro-
vided. The two parts of the mold are
swept" by formers accurately fin
ished from thin iron to the form intend
ed for the inner and outer surfaces Of
the bell. These formers" are mount
ed and rotated over the applied loan.
Five courses Of loan and clay are sue
cessively applied, Swept and baked,
to complete each mold. Before this
work is done, however, the inner flask
is wound near the top with rope made
of hay. AS the shrinkage is very great
as the castings cool, dif1cHlty would
be met with in getting the flask and
loan out Of the nearly parallel inside
top; this pinch is obviated by using
this destructible base, which permits
the collapse of the loan after the heat
Of the metal has consumed the hay.
The five courses laid on the TASKS
are: Loan, mixture of loam, fire clay
and manure; two successive coatings
Of powdered fire clay, and, lastly, q thin
coating of brick and fire clay combined
with foundry facing. Each If these
coatings is baked in an oven before
the succeeding one is applied. The
coatings are Swept" by the formers,
as applied, both in the inner and outer
TASKS, by careful adjustments as to
thickness Of materials, SO that when
the exterior mold is placed over the in-
terror, a space corresponding to the
intended thickness and shape of the
bell shall exist. Inscriptions Of en-
bellishments to be made upon the bell
are provided for with the last coating
by means of "knurP or wheel, having
the desired motto raised upon Its peri
phery, the wheel being carefully rolled
around the soft surface and leaving its
imprint III the clay. Other designs are
impressed from dies Of the required or
nament, and the usual beading" is ac-
complished by notches in the edge Of
the sweep.
The two parts of the flask being plac-
ed together are firmly help in position
by many clamps, the tendency of hot
bell metal to squeeze through and force
a separation of TASKS being very great.
AS the mold nears completion a fire is
started in a nearby reverberatory fur
mace, in which is placed the desired
charge of copper, and when the copper
is melted the tin is added in it's proper
ton. The melted metal being ready,
the furnace is tapped, the bright stream
caught in a huge ladle swung over the
mold by a crane and poured into the
open mouth Of the mold until it is filed.
After cooling and removal from the
mold the bell is usually polished with
sand and water In special revolving
grinding machines. The tongue and
clapper, the yoke and wheel are now
and the whole suspended in
its frame. In making chime the bells
are, after completion, temporarily set
up and regularly tested by skilled bell
from the permanent Ginning
stand of the foundry.
g
one proposed for Milwaukee's city hall
has to be nodded and cast in a pit
Milwaukee Wisconsin.