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10 Fbrging-Stamping - Heat Treating January, 1925
The first attempt to apply mechanical means to
the forging operation was in the form of water wheels
for working the hammer and bellows. This must
have been as early as the fourteenth century as there
are pictures of that period illustrating the method employed.
Georgius Agricola, sometimes styled "the Father
of Metallurgy," was by far the most important author
of the sixteenth century. His great book on this subject
was published after his death by Froben at Basel,
in the vear 1556. This book seems to have been in
preparation during a period of over twenty years. He
apparently completed it in 1550, but did not send it to
press until 1553 and it did not appear until a year after
his death in 1555. He was not merely an author, but
a man of considerable importance in many public affairs
of his time and occupied repeated important posts
of public authority. In his book "De Re Metallica"
he described for the first time scores of methods and
processes which represent the accumulation of generations
of experience. His book was not excelled for
two centuries and its value to the men who followed
in this profession during the centuries can scarcely be
gauged. Illustrations shown in his book indicate that
water was not only used for power, but also for heat
treating purposes.
The blast furnace was gradually developed in Gernianv
during the first half of the fifteenth century and
with this development came the use of cast iron. The
was then worked into a mass, after which it was removed
with tongs and placed on a plate and hammered
with sledges to remove cinder, etc. It was
then reheated and hammered under a tilt hammer into
a bloom which was again reheated and hammered into
a bar.
The tilt hammer was so called because its action
depended upon the shaft or helve being tilted up and
FIG. A—Old-fashioned water driven trip hammer, from
Overmann's "Manufacture of Steel," 1854.
then allowed to fall. The helve was tilted by means
of projections fitted into a drum which was fixed upon
a shaft. When the shaft revolved these projections
caught against the helve, causing it to tilt up for a
moment, but instantly releasing as the projection disengaged,
allowing the helve to drop by gravity. The
/die on the hammer being fixed on one end of the helve,
struck a blow on the stock placed on the anvil underneath.
The rapidity of action depended on the speed
at which the shaft revolved and also on the number
of projections in the drum. The speed varied from
60 to 300 blows per minute.
There were three types of these hammers, viz;
belly, nose and tail hammers, named from the positions
on the helves where the projections on the drum operated.
It was my privilege to witness the operation
of a belt-driven tail hammer in Indiana only a few
weeks ago. This hammer was used in the forging of
small adz and sledges and was capable of striking
about 500 blows per minute. Of course, the force of
blow and rapidity of action were constant and could
not be varied; stopping the hammer merely consisted
of shifting the belt and allowing the pulley to gradually
lose momentum, eventually stopping the hammer.
Up until the seventeenth century charcoal was
used in the manufacture of pig iron, but the enormous
consumption of wood threatened the destruction of
the forests, so that in the early days of Queen Elizabeth's
reign (about 1558) the cutting of timber trees
was forbidden in certain parts of the country. Thus
iron making in England received a severe setback
until early in the seventeenth century Dud Dudley, a
youth of 20, left Oxford University to take charge of
his father's furnaces and forges. He carried on experiments,
using pit or sea coal instead of charcoal for
smelting iron and was granted a patent by King
James. Dudley's furnace was larger than the average,
haying very large bellows and he thus succeeded
in making about seven tons of pig iron per week.
FIG. 3—The old Oliver footpower hammer.
However, a combination of charcoal iron masters opposed
the innovation, forcing him from one enterprise
first casting of cannon balls took place in Germany, to another so that his discovery was not very profit­
the first cast-iron cannon being made in England in able for him financially. His book "Metallum Mar-
1543.
-tis," published in 1665, gives a full account of his ef­
The method of converting pig iron into wrought forts to substitute coal for charcoal. The production
iron during the fifteenth century is roughly described sof charcoal pig iron has survived until today, the most
as follows: One end of the pig was heated in the notable operation being that of the Salisbury Iron
furnace and as it melted away was gradually pushed Corporation at Lakeville, Conn., where there were at
in until the entire stock was molten. The molten iron various times as many as thirty-one charcoal blast