The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1873-04-05

Rolling Mill Notes.

! 1t is estimated that one tenth Of the en-
/ tire population Of the | nited States is de
| pendent for support upon the production
and manufacture uf iron. The value uf
| the rhetal annually manufactured il $500.
900, 900, and 94O, 900 workmen are employ
ed in the industry, the aggregate Of whose
wages reaches S6OO, 900, OOO There has
been a vast increase Of furnace capacity
and additional machinery put III by our
rolling mills during the past eight Or ten
months and there is every prospect of still
| further growth.
We are indebted to a pamphlet lately
ISSUED by Messrs Lewis and Rossiter, Of
Pittsburgh, Pa. for the following interest
my information III reference to iron and
rolling mills Regarding material, Eng
hsh and American irons differ from each
other III certain general characteristics
Ameri, an is softer than English As re-
sptcts resistance to tensile strain, 1t ismOre
ductile and tougher while yielding more
readily t. immediate force. 1t will stand a
greater ultimate strain Il also undergoes
vibration without crystalizng better than
does English iron. The latter, being hard
er, stands greater immediate tensll strain
but yields to less ultimate force The
same general difference exists as regards
compresslve STRAIN.
Ii bar of iron Is measured and found
to be exactly one foot long when cold. al
ter Il Is heated to darkIsh yellow it will
have expanded from one-eighth to one
quarter of an inch in its length, varying
With the degree Of heat used and the uual-
ity Of the bar IL fellows, then. that in
order to turn rolls which shall produce a
definite section If iron. the last groove
shorld be made somewhat larger than the
sect n desired 1t requires considerable
experience and practice to place the exact
amount II contraction III bars ~ comp.
Gated sections. The most accurate way Of
measuring the contraction - by means of It
double ended calhper. having one side
longer than the other. 4 very convenient
size for use is when one side measures 4 !
inches and the other - 64 inches from
center t. tips. For finishing work in roll
turning the best Of steel should be used /;
but in turning up and roughing out hard
iron, cast iron cutters chilled on the sur
face may be employed to advantage 1t is
also advisable to use water IN turning up
hard iron or soft iron with fast speeds
Fire, under rolling mills that have been
built on made ground, has been the occa-
sion uf much trouble Some Of the mill
owners. to prevent a recurrence Of dam
age, have caused to be laid. beneath new
furnaces, brick paving some two ur three
feet IN depth and wider than the base Of
the furnace usually requires Others
when making ground, have mixed common
earth with the cinders that are thrown
from the mill Lately fire under PITTS
burgh establishment burned over one year
and was then only extinguished by All un-
usually high flood III the river When lay
ing foundations for machinery on ground
made from rolling mill refuse, the pits
should be dug low enough to reach solid
ground, and then only the floor will sink
| in the event Of fire.
An ingenious way Of getting speeds for a
roll train has recently been put in practice
The train has two sets of pinions and two
sets Of housings which, of course, are IN
the usual position between the roughing
rolls and the crab. The pinions nearest
the crab are different in diameter the
top one being the smallest. Between these
two sets Of pinions, but one spindle is EN-
| ployed, and by using this spindle on the
top plnIOns, the fastest speed is gained
| by using it on the larger middle pInion
the train is made to run slower and by
dropping to the lower and largest plnion
the slowest required speed is obtained
Between the first set Of pinions and the
crab is the usual breaking spindle. always
coupled to the middle pinion and between
the second set of piniOns and the roughing
rolls are the three spindles these are new
er changed. The idea was put Ill use with
an eight inch guide train that could not
otherwise be well altered from the original
mode Of driving. The plan is capable Of
further application.
rail mill pinion has been in use for the
\ last twelve months with two false teeth
/ which were put in as follows A dOvetail
| groove was cut about one inch below the
roots Of the teeth and cast iron piece hav-
| ing two teeth was nicely fitted in. This
| piece IS firmly held in position BY two
wrought iron bands shrunk ON each end
near the teeth. A strengthening plate,
after getting hollow ON its surface through
use, has been Strengthened by hammering
on its concave sides. A good steel punch
is capable Of piercing through thickness
Of iron equal to the diameter Of the punch.
/ n COTTcSpOhuonl, TeioTEln2 70 Ino rOlllnI
mills Of Belgium, says that they are buI
poorly managed. The largest establish
ment is the John Cockerill works at Sera-
ing on the river Meuse. The buildings
cover one hundred acres and twelve thou.
sand hands are employed Locomotives
and marine engines Of the most powerful
form are constructed. The company has
its own coal mines and blast furnaces.
pnoA Qhna and TAakhar nru;raa.