Dodgeville chronicle. [volume] (Dodgeville, Wis.) 1862-current, 1867-11-29
Peculiarities of Machines.
THEIR INDIVIDUALITY.


An article cut from an exchange has re-
yiyed in our mind some recollections which
may have practical bearing. Years ago
we had some personal experience as a
builder and manager of steam engines,
both stationary and locomotive, and we
had noticed the peculiarities of machines,
which, according to the rules of mechan-
ical skill and the exactness of human en-
deavor, should be alike, yet which pre-
scented such marked points of difference, if
not of divergence, that mechanical talent
was entirely at fault to account for the
variation. e43
Every experienced engineer-to take
steam engines as sample-has noticed
frequently, or repeatedly, that while one
engine developed its full amount of power,
or that quota which was expected of it,
another, built after the same patterns, with
the same tools, and by the same workmen,
failed to fulfill the design of the con-
structCr. t Ii ts{ sac at
Sometimes it is difficult, if not impossi-
Bile, to account for these differences, but it
is noticeable that they are the more marked
as the machinery is the more complex, so
| that it is natural to suppose that there is,
somewhere in the details, a difference OF
construction, otherwise we must impute
the variation to some mysterious agency
| whose operations are irremediable by me-
chanical skill But even when the ma
chine or implement is simple in its parts
and built after unvarying cages, the differ
ences may occasionally be detected. The
little pocket pistol which may be one OF
/ thousands built by the same machinery
and workmen will, in some cases, differ
widely in its execution from others OF the
same lot, when careful comparison fails
to detect the reason. That there must be
some variation either in quality or material
or construction the mechanic is assured
but he may not be able to ascertain what ii
is. Sometimes, however, the cause Of diff
1 ference may be detected. A case in point
which we remember, was that of two loco.
motives running on the same road, the ma
chimes being so nearly alike that Their
parts were interchangeable yet which diff
fered widely in their respective perform
ances. Repeated examinations of the
working parts failed to reveal the cause
! The engineer of the inferior machine spent
many hours in "tinkering and coax
ing" his engine, yet still it refused to per
form the work of it's mate. AS a last re
sort he measured the apertures OF the ex
haust pipes on both engines, and fOunt
that while those of the rival machine
measured one-and-a, quarter inches, biz
measuredone and three eighths inches. Tht
| pipes being of copper, he "drew in /" those
of his engine one eighth of an inch, wheI
it performed even better than the other
owing, undoubtedly, to the better care
which had been taken OF 1t and its more
perfect condition. The difference in the
diameter of these pipes was but trifle, We
no doubt it was the reason CT the variation
d in the work of the two locomotives.
4 So it may be often that slight chang,
in the proportions or the actual dimen
sions of parts may insure evenness ant
1 accuracy where the divergence and uncer
tainty may have been remarkable and mys
FERROUS. To ascertain and remedy thes
, points Of difference is the province of tn
intelligent, practical, and educated OILS
chanic Exactness and accuracy in to me
, of which we spoke in recent number