A forge like the one whose plan we give, may be run with 1 workman at
the cadinhes, 1 assistant, 1 workman at the hammer; total, 3 men.
_Furnace_.--The work lasts about twelve hours per day, and three
operations of three to four hours are performed in each cadinhe, thus
making twelve per day. At each operation, 22.5 kilos. of ore and 45 of
charcoal are used. From this there is obtained a bloom of 15 kilos. The
operation is performed as follows:
While the assistant has gone to put the bloom of the preceding operation
under the hammer, the workman prepares at the bottom of the crucible a
bed consisting of a mixture of sand and very fine charcoal, and then
fills the crucible up to its edge with charcoal. At the end of a quarter
of an hour, the fuel being thoroughly aglow, the workman puts in the
first charge of ore in powder (_jacutingue_), about 2 kilos, and covers
it with charcoal.
Starting from this moment, he goes on charging every five or ten minutes
with 1.5 to 2 kilos of ore, taking care in doing so to keep the crucible
stuffed with charcoal, which the assistant places in piles around each
cadinhe. This lasts about two and one-half hours. At the end of this
time he stops putting in charcoal, and standing upon the masonry, walks
from one cadinhe to another, carrying a large rod, in order to study the
lay of the bloom. Then, the fire being entirely out, he scrapes out the
bed of sand and charcoal that closes the opening in the bottom of the
crucible, removes the mass of ferruginous scoriæ which forms a hard
paste and surrounds the bloom, and takes this latter out by means of a
hook.
The workman runs the four cadinhes at once, this being easily enough
done, since he has neither to bother himself with regulating the wind,
which enters always with the same pressure, nor with the flow of the
scoriæ, which remain always at the bottom of the crucible. His role
consists simply in keeping his fires running properly, being guided in
this by the color of the flame without making an examination in the
interior. He draws each of the four blooms out from its bed at the end
of the operation, while the assistant carries the first to the hammer
and the three others to the reheating furnace. He afterward cleans
out the crucible, prepares the bed of sand and charcoal, fills with
charcoal, and then passes to the next, and so on.
[Illustration: FIG. 5.--REHEATING FURNACE.]
_Trip Hammer_.--The workman at the hammer takes the bloom from the hands
of the assistant and shingles it under the head. Then he begins to give
it shape, bringing it to the state shown at c, in Fig. 7. The assistant
then brings him another bloom and takes the one that has been shingled
to the reheating furnace, where he heats but one of its extremities.
When the four blooms have been shingled, the workman takes up the first
and begins to draw out one of its extremities, which he afterward cools
in water and uses as a handle for finishing the work, d. Then he reheats
the other extremity, and, after drawing it out as he did the other,
obtains a bar of finished iron which he doubles, as shown at e, to thus
deliver to the trade.
[Illustration: FIG. 6.--CADINHE IN OPERATION.]
One of these bars weighs from 11 to 12 kilogrammes. It will be seen
that, during the course of the work, the furnace workmen and the hammer
workmen have well defined duties to perform; but it is not the same with
the assistant, who goes from one to the other according to requirements.
There are, however, some forges in which each of the workmen has an
assistant, since the blooms produced are heavier, and one assistant
would not suffice for the work of the two men. In such a case the
assistant at the crucibles carries the blooms to the reheating furnace,
and the assistant at the hammer carries them from thence to the hammer.
[Illustration: FIG. 7.--WORKING THE BLOOM.]