METAL WORKING.
We referred in the last chapter to the fact that metal when it came from
the melting and puddling furnace was formerly rolled into sheets; but,
when the manufacturers and consumers got these sheets then came the
severe, laborious work by hand of cutting, hammering, boring, shaping
and fitting the parts for use and securing them in place.
It is one of the glories of this century that metal-working tools and
machinery have been invented that take the metal from its inception,
mould and adapt it to man’s will in every situation with an infinite
saving of time and labour, and with a perfection and uniformity of
operation entirely impossible by hand.
Although the tools for boring holes in wood, such as the gimlet, auger,
and the lathe to hold, turn and guide the article to be operated on by
the tool, are common in some respects with those for drilling and
turning metal, yet, the adaptation to use with metal constitutes a class
of metal-working appliances distinct in themselves, and with some
exceptions not interchangeable with wood-working utensils. The
metal-working tools and machines forming the subject of this chapter are
not those which from time immemorial have been used to pierce, hammer,
cut, and shape metals, directed by the eye and hand of man, but rather
those invented to take the place of the hand and eye and be operated by
other powers.
It needs other than manual power to subdue the metals to the present
wants of man, and until those modern motor powers, such as steam,
compressed air, gas and electricity, and modern hydraulic machinery,
were developed, automatic machine tools to any extent were not invented.
So, too, the tools that are designed to operate on hard metal should
themselves be of the best metal, and until modern inventors rediscovered
the art of making cast steel such tools were not obtainable. The
monuments and records of ancient and departed races show that it was
known by them how to bore holes in wood, stone and glass by some sharp
instruments turned by hand, or it may be by leather cords, as a top is
turned.
_The lathe_, a machine to hold an object, and at the same time revolve
it while it is formed by the hand, or cut by a tool, is as old as the
art of pottery, and is illustrated in the oldest Egyptian monuments, in
which the god Ptah is shown in the act of moulding man upon the throwing
wheel. It is a device as necessary to the industrial growth of man as
the axe or the spade. Its use by the Egyptians appears to have been
confined to pottery, but the ancient Greeks, Chinese, Africans, and
Hindoos used lathes, for wood working in which the work was suspended on
horizontal supports, and adapted to be rotated by means of a rope and
treadle and a spring bar, impelled by the operator as he held the
cutting tool on the object. Joseph Holtzapffel in his learned work on
_Turning and Mechanical Manipulation_, gives a list of old publications
describing lathes for turning both wood and metal. Among these is
Hartman Schapper’s book published at Frankfort, in 1548. A lathe on
which was formed wood screws is described in a work of Jacques Besson,
published at Lyons, France, in 1582.
It is stated that there is on exhibition in the Abbott museum of the
Historical Society, New York, a bronze drinking vessel, five inches in
diameter, that was exhumed from an ancient tomb in Thebes, and which
bears evidence of having been turned on a lathe. It is thought by those
skilled in the art that it was not possible to have constructed the
works of metal in Solomon’s Temple without a turning lathe. One of the
earliest published descriptions of a metal turning lathe in its leading
features is that found in a book published in London, in 1677-83, by
Joseph Moxon, “hydographer” to King Charles II., entitled, _Mechanical
Exercises, or the Doctrine of Handy Works_. He therein also described a
machine for planing metal. Although there is some evidence that these
inventions of the learned gentleman were made and put to some use, yet
they were soon forgotten and were not revived until a century later,
when, as before intimated, the steam engine had been invented and
furnished the power for working them.
Wood-working implements in which the cutting tool was carried by a
sliding block were described in the English patents of General Sir
Samuel Bentham and Joseph Bramah, in 1793-94. But until this century,
and fairly within its borders, man was content generally to use the
metal lathe simply as a holding and turning support, while he with such
skill and strength as he could command, and with an expenditure of time,
labour and patience truly marvellous, held and guided with his hands the
cutting tool with which the required form was made upon or from the
slowly turning object before him. The contrivance which was to take the
place of the hand and eye of man in holding, applying, directing and
impelling a cutting tool to the surface of the metal work was the
_slide-rest_. In its modern successful automatic form Henry Maudsley, an
engineer in London, is claimed to be the first inventor, in the early
part of the century. The leading feature of his form of this device
consists of an iron block which constitutes the rest, cut with grooves
so as to adapt it to slide upon its iron supports, means to secure the
cutting tool solidly to this block, and two screw handles, one to adjust
the tool towards and against the object to be cut in the lathe, and the
other to slide the rest and tool lengthwise as the work progresses,
which latter motion may be given by the hand, or effected automatically
by a connection of the screw handle of the slide and the rotating object
on the lathe.
A vast variety of inventions and operations have been effected by
changes in these main features. Of the value of this invention, Nasmyth,
a devoted pupil of Maudsley and himself an eminent engineer and
inventor, thus writes:--“It was this holding of a tool by means of an
iron hand, and constraining it to move along the surface of the work in
so certain a manner, and with such definite and precise motion, which
formed the great era in the history of mechanics, inasmuch as we
thenceforward became possessed, by its means, of the power of operating
alike on the most ponderous or delicate pieces of machinery with a
degree of minute precision, of which language cannot convey an adequate
idea; and in many cases we have, through its agency, equal facility in
carrying on the most perfect workmanship in the interior parts of
certain machines where neither the hand nor the eye can reach, and
nevertheless we can give to these parts their required form with a
degree of accuracy as if we had the power of transforming our-selves
into pigmy workmen, and so apply our labour to the innermost holes and
corners of our machinery.”
The scope of the lathe, slide-rest and operating tool, by its adaptation
to cut out from a vast roll of steel a ponderous gun, or by a change in
the size of parts to operate in cutting or drilling the most delicate
portions of that most delicate of all mechanisms, a watch, reminds one
of that other marvel of mechanical adaptation, the steam hammer, which
makes the earth tremble with its mighty blows upon a heated mass of
iron, or lightly taps and cracks the soft-shelled nut without the
slightest touch of violence upon its enclosed and fragile fruit.
The adaptation of the lathe and slide to wood-working tools will be
referred to in the chapter relating to wood-working.
Following the invention of the lathe and the slide-rest, came the
_metal-planing_ machines. It is stated in Buchanan’s _Practical Essays_,
published in 1841, that a French engineer in 1751, in constructing the
Marly Water Works on the Seine in France, employed a machine for planing
out the wrought iron pump-barrels used in that work, and this is thought
to be the first instance in which iron was reduced to a plane surface
without chipping or filing. But it needed the invention of the
slide-rest and its application to metal-turning lathes to suggest and
render successful metal-planing machines. These were supplied in England
from 1811 to 1840 by the genius of Bramah, Clement, Fox, Roberts,
Rennie, Whitworth, Fletcher, and a few others. When it is considered how
many different forms are essential to the completion of metal machines
of every description, the usefulness of machinery that will produce them
with the greatest accuracy and despatch can be imagined. The many
modifications of the planing machine have names that indicate to the
workman the purpose for which they are adapted--as the _jack_, a small
portable machine, quick and handy; the _jim crow_, a machine for planing
both ways by reversal of the movement of the bed, and it gets its name
because it can “wheel about and turn about and do just so”; the key
groove machine, the milling machine with a serrated-faced cutter bar,
shaping machine and shaping bar, slotting machine, crank planer, screw
cutting, car-wheel turning, bolt and nut screwing, etc.
As to the mutual evolution and important results of these combined
inventions, the slide-rest and the planer, we again quote Nasmyth:--
“The first planing machine enabled us to produce the second still
better, and that a better still, and then slide rests of the most
perfect kind came streaming forth from them, and they again assisted in
making better still, so that in a very short time a most important
branch of engineering business, namely, tool-making, arose, which had
its existence not merely owing to the pre-existing demand for such
tools, but in fact raised a demand of its own creating. One has only to
go into any of these vast establishments which have sprung up in the
last thirty years to find that nine-tenths of all the fine mechanisms in
use and in process of production are through the agency, more or less
direct, of the _slide rest and planing machine_.”
Springing out of these inventions, as from a fruitful soil, came the
metal-boring machines, one class for turning the outside of cylinders to
make them true, and another class for boring and drilling holes through
solid metal plates. The principle of the lathe was applied to those
machines in which the shaft carrying the cutting or boring tool was held
either in a vertical or in a horizontal position.
Now flowed forth, as from some Vulcan’s titanic workshop, machines for
making bolts, nuts, rivets, screws, chains, staples, car wheels, shafts,
etc., and other machines for applying them to the objects with which
they were to be used.
The progress of screw-making had been such that in 1840, by the machines
then in use for cutting, slotting, shaving, threading, and heading,
twenty men and boys were enabled to manufacture 20,000 screws in a day.
Thirty-five years later two girls tending two machines were enabled to
manufacture 240,000 screws a day. Since then the process has proceeded
at even a greater rate. So great is the consumption of screws that it
would be utterly impossible to supply the demand by the processes in
vogue sixty years ago.
In England’s first great International Fair, in 1851, a new world of
metallurgical products, implements, processes, and metal-working tools,
were among the grand results of the half century’s inventions which were
exhibited to the assembled nations. The leading exhibitor in the line of
self-acting lathes, planing, slotting, drilling and boring machines was
J. Whitworth & Co., of Manchester, England. Here were for the first time
revealed in a compact form those machines which shaped metal as wood
alone had been previously shaped. But another quarter of a century
brought still grander results, which were displayed at the Centennial
Exhibition at Philadelphia, in 1876.
As J. Whitworth & Co. were the leading exhibitors at London in 1851, so
were William Sellers & Co., of Philadelphia, the leading exhibitors in
the 1876 exhibition. As showing the progress of the century, the
official report, made in this class by citizens of other countries than
America, set forth that this exhibit of the latter company, “in extent
and value, in extraordinary variety and originality, was probably
without parallel in the past history of international exhibitions.”
Language seemed to be inadequate to enable the committee to describe
satisfactorily the extreme refinement in every detail, the superior
quality of material and workmanship, the mathematical accuracy, the
beautiful outlines, the perfection in strength and form, and the
scientific skill displayed in the remarkable assemblage of this class of
machinery at that exhibition.
An exhibit on that occasion made by Messrs. Hoopes & Townsend of
Philadelphia attracted great attention by the fact that the doctrine of
the flow of solid metal, so well expounded by that eminent French
scientist, M. Tresca, was therein well illustrated. It consisted of a
large collection of bolts and screws which had been _cold-punched_, as
well as of elevator and carrier chains, the links of which had been so
punched. This punching of the cold metal without cutting, boring,
drilling, hammering, or otherwise shaping the metal, was indeed a
revelation.
So also at this Exhibition was a finer collection of machine-made
horseshoes than had ever previously been presented to the world. A
better and more intelligent and refined treatment of that noble animal,
the horse, and especially in the care of his feet, had sprung up during
the last half century, conspicuously advocated by Mr. Fleming in
England, and followed promptly in America and elsewhere. Within the last
forty years nearly two hundred patents have been taken out in the United
States alone for machines for making horseshoes. Prejudices, jealousies
and objections of all kinds were raised at first against the
machine-made horseshoe, as well as the horseshoe nail, but the horses
have won, and the blacksmiths have been benefited despite their early
objections. The smiths make larger incomes in buying and applying the
machine-made shoes. The shoes are not only hammered into shape on the
machine, but there are machines for stamping them out from metal at a
single blow; for compressing several thicknesses of raw hide and
moulding them in a steel mould, producing a light, elastic shoe, and
without calks; furnishing shoes for defective hoofs, flexible shoes for
the relief and cure of contracted or flat feet, shoes formed with a
joint at the toe, and light, hard shoes made of aluminium.
_Tube Making._--Instead of heating strips of metal and welding the edges
together, tubes may now be made seamless by rolling the heated metal
around a solid heated rod; or by placing a hot ingot in a die and
forcing a mandrel through the ingot. And as to tube and metal bending,
there are wonderful machines which bend sheets of metal into great
tubes, funnels, ship masts and cylinders.
_Welding._--As to welding--the seams, instead of being hammered, are now
formed by melting and condensing the edges, or adjoining parts, by the
electric current.
_Annealing and Tempering._--Steel wire and plates are now tempered and
annealed by electricity. It is found that they can be heated to a high
temperature more quickly and evenly by the electric current passed
through them than by combustion, and the process is much used in making
clock and watch springs.
One way of hardening plates, especially armour plates, by what is called
the Harveyized process, is by embedding the face of the plate in carbon,
protecting the back and sides with sand, heating to about the melting
point of cast iron, and then hardening the face by chilling, or
otherwise.
_Coating with Metal._--Although covering metal with metal has been
practised from the earliest times, accomplished by heating and
hammering, it was not until this century that electro-plating, and
plating by chemical processes, as by dipping the metal into certain
chemical solutions, and by the use of automatic machinery, were adopted.
It was in the early part of the century that Volta discovered that in
the voltaic battery certain metallic salts were reduced to their
elements and deposited at the negative pole; and that Wollaston
demonstrated how a silver plate in bath of sulphate of copper through
which a current was passed became covered with copper. Then in 1838,
Spencer applied these principles in making casts, and Jacobi in Russia
shortly after electro-gilded a dome of a cathedral in St. Petersburg.
Space will not permit the enumeration of the vast variety of processes
and machines for coating and gilding that have since followed.
_Metal Founding._--The treatment of metal after it flows from the
furnaces, or is poured from the crucibles into moulds, by the operations
of facing, drying, covering, casting and stripping, has given rise to a
multitude of machines and methods for casting a great variety of
objects. The most interesting inventions in this class have for their
object the chilling, or chill hardening, of the outer surfaces of
articles which are subject to the most and hardest wear, as axle boxes,
hammers, anvils, etc., which is effected by exposing the red-hot metal
to a blast of cold air, or by introducing a piece of iron into a mould
containing the molten metal.
In casting steel ingots, in order to produce a uniform compact
structure, Giers of England invented “soaking pits of sand” into which
the ingot from the mould is placed and then covered, so that the heat
radiating outward re-heats the exterior, and the ingot is then rolled
without re-heating.
_Sheet Metal Ware._--Important improvements have been made in this line.
Wonderful machines have been made which, receiving within them a piece
of flat metal, will, by a single blow of a plunger in a die, stamp out a
metal can or box with tightly closed seams, and all ready for the cover,
which is made in another similar machine; or by which an endless chain
of cans are carried into a machine and there automatically soldered at
their seams; and another which solders the heads on filled cans as fast
as they can be fed into the machine.
_Metal Personal Ware._--Buckles, clasps, hooks and eyelets, shanked
buttons, and similar objects are now stamped up and out, without more
manual labour than is necessary to supply the machines with the metal,
and to take care of the completed articles.
_Wire Working._--Not only unsightly but useful barbed wire fences, and
the most ornamental wire work and netting for many purposes, such as
fences, screens, cages, etc., are now made by ingenious machines, and
not by hand tools.
In stepping into some one of the great modern works where varied
industries are carried on under one general management, one cannot help
realising the vast difference between old systems and the new. In one
portion of the establishment the crude ores are received and smelted and
treated, with a small force and with ease, until the polished metal is
complete and ready for manipulation in the manufacture of a hundred
different objects. In another part ponderous or smaller lathes and
planing machines are turning forth many varied forms; in quiet corners
the boring, drilling, and riveting machines are doing their work without
the clang of hammers; in another, an apparently young student is
conducting the scientific operation of coating or gilding metals; in
another, girls may be seen with light machines, stamping, or burnishing,
or assembling the different parts of finished metal ware; and the motive
power of all this is the silent but all-powerful electric current
received from the smooth-running dynamo giant who works with vast but
unseen energy in a den by himself, not a smoky or a dingy den, but
light, clean, polished, and beautiful as the workshop of a god.