Herald and news. [volume] (West Randolph, Vt.) 1878-1943, 1889-01-24
HOW CELLS ARE MADE.
OPERATIONS REQUIRING GREAT
CARE AND SKILL
The Musical Tone Forming the
Misunderstanding and Polishing
the BeII-Testfng the Tone

Misunderstanding and Polishing
the BeIl-TestfnR the Tone.
It may not be generally known, says a
writer in Stones and Hardware, that there
are only five concerns in the United
States engaged in the manufacture of
church, school, and chime bells.
Contrary to the popular idea, the ex-
act musical tone of bell depends neither
upon the metal nor upon any change in
1t after being cast. II the bell should
not be of the exact pitch, there is no
alternative but to melt it over and re-
cast it until the proper tone is secured.
Hence, it is clear that the greatest care
must be exercised, and the most thor
ough skill displayed.
The first operation, and the one upon
which success depends, is the forming
of the moulds. They are made accord
ing to plans which are first prepared to
demonstrate the weight, thickness, and
dimensions necessary to produce the re-
quired tone. The moulding is done co.
tirely by hand, without the use of pat
terms. For the inside, the shape is made
up of loan, which is merely sand mixed
with enough clay to make it cohesive.
With nothing but trowel, a paddle,
and his hands, the operator moulds the
loan into the desired shape, work.
ing from the bottom toward the apex.
The work is necessarily slow, as great
care must be exercised, as any variation
from the plans would inevitably ruin the
effect, and frequent measurements are
taken 10 see that there are no deviations.
The surface is now covered with black
lead. This is mixed into thick paint,
or mortar, and applied with a brush.
Each coat must be allowed to dry, and
successive coats applied until it reaches
a thickness of about three-quarters OF an
inch, OF until the desired shape is ac-
curaiely secured. The outside half of
the mould is built up Of loan in the
same way, only in this case no coating of
plnmbago is used. The exterior mould
fits over the inside mould, the space be-
tween the two determining the thickness
OF the bell The moulds being finished,
they are placed in position in pit in
front of the furnace. At the apex, or
at the point where the bell would be
hung. an opening is made in the outside
mould of about two inches in diameter.
A trough then carries the molten metal
directly into the mould.
The furnace is very similar to those
generally used in melting large guam
titles of brass. The melting pot is built
between two fre-boxes, so constructed
that the heat strikes the sides and boz
tom with almost equal force. Getting
quick results. The metal used is simply
ingot copper and tin, in the proportion
OF four parts Of the former to one CT the
latter. The copper is first melted, and
then the tin is put into the molten mass,
soon becoming part of it. The kettle
has a capacity of about a ton. For
bell weighing three hundred pounds, the
mould is completely tilled in seven or
eight minutes. For bells weighing six
hundred pounds, it requires about fifteen
minutes, and so on.
The bell having cooled sufficiently,
the moulds are broken, and it is taken
out and turned over to the polisher. The
inside. having been moulded against the
smooth surface Of black lead, needs no
polishing, but the outside requires at
tention in that respect. The operation
is very simple. The bell is hoisted to
the center Of a double revolving table.
The part the bell rests upon revolves
one way, the surrounding part in an
opposite direction. This latter part is
SO constructed that it will hold large
quantity of coke. Thus, in revolving,
the coke scours the outside of the bell,
the result being q smooth, bright sur
face.
Before polishing, however. the tone of
the bell is tested, and it is again tested
after polishing, as carefully as the string
of piano or the reed of an organ. If
satisfactory, nothing remains to do but
the mounting.
An idea of the great accuracy that
must be displayed in the plans and prep.
aration of the moulds can be seen in that
from ten to twenty-five pounds of metal,
either too much or too little, in bells
weighing from 600 to 1000 pounds, or
variation Of from one-twentieth to one
twelfth Of an inch in thickness, will affect
the tone. The successful manufacture
of chimes and peals, therefore, can only
be done by those whose knowledge of
the business is as accurate as instinct,
and this is possessed only by those who
have followed the business for lifetime.
Tho Rigpast paying Stone