The sun. [volume] (New York [N.Y.]) 1833-1916, 1899-09-17
AMERICAN MAoaIxrnE.
An Expert's Reasons for fits Unrivsiied
Excellence.
From Cossiey's Mdoorine.

From Casters Magazine.
With the noteworthy extension Of the market for
American machinery and machineshop products
the features which distinguish the American
methods OF construction and design from those Of
other nations have acquired widespread COM
mercial interest
II has been often stated that the American
method is TO manufacture machinery on the inter-
changeable plan; OF that tho only difference be-
tween 1t and the methods of other countries is in
the extensive use of automatic machinery; and,
again, II has been stated that Americans make
better machinery because they concentrate their
attention on spccialties. This, however. is only
half tho truth. The American method and 1t is a
vital point in the American system, is to work be-
tween iSsl predetermined limits OF naccuracy or
error. Other builders make their machine details
more or less imperfect and correct the faults as
well as may be in the assembling, while Americans
seek to have the details right and perfect reducing
10 the lowest possible the number and importance
OF the imperfection4
To the public mind machine is Just an assem-
bage Of shafts, wheels and details which go when
power is applied TO move them Comparatively
few know that II those shafts do not fit the bear
ings in Just a certain way, and that II the axial
centre lines of the shafts are not almost mathe-
matcally correct the machine will fail TO work.
and that the inaccuracy which, if too great en-.
sures the breaking down OF the machine, must not
exceed, in many cases, a few thouSandlhS OF an
inch. Take, for example, pulley turning on a
shaft-an elementary machine. The pulley ia
put In lathe and the hole In bored for the shaft
Tho first difficulty is met at once all lathcs are
Inaccurate; none bores round straight hole OF
like diameter throughout. The bore of the pulley
will be more or less out Of round, crooked and
taperine. Wherever the bore is out of round
apering or crooked al those points the surface of
the shaft will squeeze out the oil and will rub
against the surface Of the pulley, and If tho in
accuracy be beyond certain limits, the wearing sur
faces will be destroyed as though there had been
no lubricant On the other hand, the life Of the
wearing surfaces will be prolonged indefinitely if
the bore OF the pulley and the shaft absolutely
straight round and uniform, with smooth, highly
polished surfaces, and if the shaft diameter were
OF exactly the size TO allow the oil TO flow between il
and the pulley. The fitting Of a machine there
fore is OF the highest Importance: even a well
designed machine may be wrecked by incorrect fit
ting and the life wear OF every machine is de
pendent on the workmanship shown in this matter
In case Of the pulley and the shaft tho error
allowable in practice Is quito large. Tho shaft
may shake In the pulley bore, the difference in
the respective d meters may be one hundredth Of
an inch without harm, hut is altogether another
ing presses, for instance where there is a sc: cs
OF successive operations, such error can DO
tolerated Here the movements arc driven by
gearing trains, and II the shafts shook ever SO
little in their bearings, the ink roller would dis
tribute the ink uneveny the time OF the opera
lions would become irregular and the gear teeth
would break. Here, then. very close fitting Is
Indispensable, and the error limit would be
pressed in a very few thousandths Of an inch
In the town OF Liege, Belgium, a very important
industry Ii the manufacture OF revolvers and
other small arms The details Of these are given
by contract 10 workmen. who finish them at their
homes. all the work being done by hand. prao-
tically. These details when finished brought
TO the factory where they assembled. The
filter, having lot OF details before him. selects
a set and proceeds TO make one piece match the
other. There Ia nothing standard about these
details, and each revolver or gun made under
this system Is unlike the other. Tho grade OF
the work and fitting depends entirely upon the
skill and good faith Of the individual workman
and when out OF order the entire piece must be
returned to the factory. Obviously this would
be q wretched weapon wherewth to fit out an army.
In this manner all firearms woro manufactured
until the beginning Of this century
When Eli whitney, the inventor Of the cotton
gin, unable p secure his ghts for that inven
ton and found himself loaded down with debts
incurred in the attempt he could never have sus-
peced that to be blessing in dsg use To his
country and even 70 him. Seeing no prospect Of
obtaining justice, ho turned his ingenious mind
into another path. and In 1913 he took contract TO
furnish 10 900 stands Of arms 70 the United States
Government The time for fulfilling tho contract
was two years
To appreciate tho difficulties Of his undertaking
we should bear In mind that there were few work.
men and but little knowledge OF the art of gun
making in the United States, and there
machine tools. The milling machine had been
described in Franco in some publications, but not
one was In use in America TWAS probably in tho
end an advantage to Whitney that he was forced 10
think out an entirely novel way 70 manufacture his
guns He not only an inventor, but also
remarkable workman, having been accustomed,
from his earliest boy hood 10 exercise all the trades
in addition 10 being a hard student and close OBJ
server He was driven by the force of clrcum-
stances TO base his plan of manufacture upon MAX
ing the parts of his guns alike and of uniform
cellence by special tools. His contract took Gig hit
years in place Of two. but il completed TO tho
perfect satisfaction OF tho government He con-
tnued TO take similar contracts until his death
His factory was near New Haven Conn. at tho
present village Of Whitneyvlle; and out of this
place came the Yankee tool-maker another school
master who was destined u educate the world in
the art OF ironmaking. To explain Whitneys
method let us consider again the pulley and shaft
We have that il is very difficult and time
killing TO bore out the pulley in LATHE with turn
ing tool. dozen pulleys bored out in this way
would all have different dameters They may be
likened TO the details made by the Lege gun
smiths Each shaft would have TO he turned by
itself TO Al particular pulley; each would fl only
one pulley. II we rough out the pulley To nearly
the desired diameter and then remove the rest Of
the tai by special tool "a reamer) we shall get
all twelve pulleys nearly alike with holes straight
and round. II. now, we make plugs one to fit the
largest and to At the smallest hole and turn the
shafts 70 sizes between the plug diamctcIs, the
shafts and pulleys will Al Interchangeable. Here
We have tho elements Of Whitney's inventions
special tools to produce extreme accuracy and per-
lection of workmanship and guagcs TO measure
and limit the amount Of departure from the
exact size desired.
In gun making, model is made which is taken
as perfect Two sets Of guages are made; one set
is kept for reference only, and the other is sent to