The record-union., 1896-07-12
BLACKSMITH SHOP.
uI.-WEIDING.


chinery in the blacksmith shop and roll
ing mill has been briefly sketched, as
has also the method of working scrap
iron by putting it through the rolls or
under the hammers, and in this arti-
Gle 1t Is proposed to give few points
connected with the most particular
work that the smith performs-that of
welding, stopping only long enough to
say that the output Of manufactured
articles from scrap iron since 1887
amounts to the enormous quantity Of
1l2,3S3,365 pounds.
The foremen and workmen of the
Southern Pacific shops in this city are
naturally familiar with the require
ments of good workmanship and the
fatal consequences of bad in welding
iron. The products of the great val
seys of the State, in order to reach
AN Eastern market, must be trans
ported either over the Tehachapi
Mountains on the south, Sierra Neya-
das on the east or the Siskiyous on the
north, to say nothing of the great Rocky
Mountain system over which the roll
ing stock is handled. Here are to be
overcome grades of more than 200 feet
to the mile, and every important mem
Der Of the great engines asked to per-
form the work passes through the
hands of the smith-the whole train be-
ing connected by one continuous chain
of welded iron
So it follows that the smiths are re-
sponsible, personally, for any accident
that may happen through their care
iessness in permitting imperfect work
TO pass through their hands. knowingly.
In the Southern Pacific shop they are
taught to appreciate the responsible
ties Of their positions, and to recognize
the fact that it Is regarded criminal in
them to hammer over and hide a de-
fecttve weld. They thoroughly under
stand that one such weld might be the
means of precipitating train down a
untain side, and that the response
bility Is in no wise lessened on descend
ing grades. The train naturally de-
ecendS by gravity and is controlled by
the most highly improved automatic
air-brake in the world. An imperfect
weld in a, brake-rod would destroy the
efficiency of each Of the four brakes on
that car, and all the ingenuity that has
been displayed in perfecting the brake,
which is applied to every car on the
Southern Pacific system to insure safe
ty to the travelling public, becomes in
operative If the work Of the smith has
been improperly done. particularly in
the welded sections of all parts con-
nected with train service.
LAP" WELDING.
The different methods of preparing
iron to be welded are governed by the
conditions and shapes of the forgings
and appliances. Lap" welding is the
usual method adopted by smiths, and is
generally considered the best, when
practicable Great care is always taken
in preparing the parts to be welded and
the scarf or overlapping edge Of the
metal, is left as long as can be convent
emily heated and never at a greater an
Gle than forty-five degrees The scarfec
surfaces are slightly convex or high ir
the center, so that when the two pieces
are laid together for welding the center
will take its bearing first, it being alb
soluteIy necessary that the center OF the
bar should be firmly knit together be-
fore the outer edges receive the greatest
pressure.
Prior to making the scarfs the bar is
upset-that is, made shorter and thicker
BY hammering as far back as it is to bt
exposed to the intense heat, for the pur-
pose of lamination, it being imperative
that the iron, which has been brough'
rear a welding heat, be as perfectly
hammered as the welded part.
After the scarfs have been completed
the two pieces are carefully laid in {
hollow fire-that is, a. furnace made ex
pressly for heating iron and at the sam'
time preserving it from contamination
bv fuel and sulphur, it being abSOlutel,
necessary that no foreign elements ad
here to the scarfed surfaces. In layin;
together. the point of one scarf mus
lust reach the heel of the other, to in
sure a perfect weld.
The weight of the hammer used t
weld the pieces IS always governed b,
the size of the bar, and not by tn
strength of the smith, as the blow mus
be sufficient to affect the center of tn
metal. so as to cause an elongation o
the molecules into fbers.
The proper treatment of the iron bacl
Of the weld is of vital Importance. Il
many cases in testing Yields by break
ing transverseIy, good fbrous iron i
found in the welded portion and crys
talIine iron on each side. The cause o
this is either improper treatment of tn
iron back of the weld or that ii was no
properly upset when brought to a higl
heat The molecular structure o
wrought iron becomes disintegrated I
a certain extent when brought to such
heat, and consequently If there is no
sufficient metal back of the welded sec
ton to allow the Iamination necessar.
to bring the disawanged molecules {
their original position, the strength o
the bar is greatly impaired
Foreman Uren has made a series o
tests on this subject, in the manufaetur
of car axles The usual method o
making axles is to first rough the pile
and then finish each half at separat
heats. For the purpose Of educating tn
employees to the Importance Of not heat
ing the finished parts of axles when n
a,ammering was to be done, the finishe
,,ortsons of two axles were placed i
IN. furnace far enough to become whit
not As soon as the unfinished part
vvere brought to the proper heat tn
axIas were finished in the usual way
ry.ha finished parts-which had bee
aroueht to a white heat-were light
1,anrnered over and sprinkled wit
water TO clear away the scales, and
a,arfect looking axle was the result.
Two other axles were then made, leav
spg a niece about six inches long an
one inch in diameter near the center c
tho axle unfinished-that is TO say, i'm
,,ranarlv laninated-close to the fin
ished part. The finished portion wa
allowed to come only to a dark red hea
and tbe axIes were then placed in tn
hammer dies and finished in the usus
way.