New-York tribune., 1919-11-16
How Tires Are
Made Is a Very
Interesting Story
Details of the Process, From
the Crude r. u b b er to
Finished Product, Told
by Firestone Man
BY E. P. Jones
M6mogsY Nesc York Firestons Tire
Branch

I
MsndgsY New York Firestone Tire
Branch
In . tour Of . tire plant we Arst
visit the large rooms in which the
crude rubber is stored. Tons Of Para
rubber are kept on hand, in the same
form as when it left the tropics.
The manufacturing process for fabric
/ tires begins when the rolls Of crude
Then they are dried in great rooms
adjoining. These drying rooms are
supplied with filtered air that has been
warmed to the proper temperature.
After it has been dried the rubber is
taken into the mill rooms, where, in
large machines, between heavy rollers
of steel which are heated by the fric-
tion of the steel's surface and the rub
Der itself, it is mixed with toughening
b pigments. There is great exactness in
following the compounding formulas,
which chemists are constantly studying.
After each lot has been forced
through the steel rolls until the mixing
is perfect the rubber is rolled into
thick sheets and sent away to be stored
or aged for q period of time. From
the aging bins the material for tubes
and tires Is taken to the calendar
rooms, whore machines carry out one
Of the most exacting processes through
which rubber is put in the building Of
tires.
1t goes into tho large calendars only
after 1t has been worked over in the
mills once more to warm and prepare
it for them. The calendars spread it
and roll it into uniform sheets OF de-
sired thickness. The sheets of rubber
that come from one set of calendars
are run through others so as to pro-
duce certain stocks for definite pur-
poses.
The building up of sheet on sheet, or
lamination, is essential to freedom
from flaw and to fneness of texture,
qualities which give life and strength
to the finished product.
Cotton fabric is of importance sec
ond only to rubber in the making of
pneumatic tire. Sea Island cotton,
when it comes into the factory, has an
inspection under tables Of magnifying
glass. Each roll is tested for thread,
weave and strength. 1t must conform
to specifications.
AS it is necessary that the fabric be
absolutely free of all atmospheric
moisture before coming in contact with
the gum rubber, it is rolled over
series of heated steel plates after 1T
has been inspected This process re-
moves the moisture without impairing
the natural tensile strength of the
cotton.
After the moisture has been taken
from the roll of cotton it is carried
on a crane to the calender rooms,
where it is rolled through the drums
of the machine against slow flow OF
the compounded rubber. The drums,
heated to a certain degree, force. the
gum into every weave and fibre of the
cloth, from one side Then the cotton
is sent through again and the warm
gum forced in from the other side.
The operation is repeated three times.
next cut into long thin rolls for use
on the tire building machines. Each
of the machines is marvel Of me.
chanics, developed through years of
experiment and study: One machine
doubles the output OF the individual
workman.
BY building up every layer Of i'm
pregnated fabric with uniform taut-
ness, the machine accomplishes what
the hand cannot do 1t lays it's last
layer at night with the same tension
that it lays its first in the morning.
The machines build the carcass of the
tire, making il Of several pieces of the
impregnated fabric.
Leaving tire machine, the carcass
goes to the hands of tire finisher.
One finsher places upon it the side
wall and bead, another the breaker
strip and the third the thread The
tire is then ready for vulcanization
or curing. Encased in steel mould, it
is lowered into steam pit, where it
is subjected to an intense steam heat
under pressure. The heat vulcanizes
the fabric and rubber into one solid
toughened bit of residence.
The steam pits are huge affairs of
steel, each of which can swallow thirty
of the steel-encased tires. After more
than an hour they have accomplished
with the tire what the process of tenn
pering does for steel. The rubber has
lost none of it's resilient qualities, but
is toughened to an almost unbelievable
degree.
After it has been lifted from the
steam pits, the finished tire is trun--
died into room where it gets an in
side coating with an ant-friction paint.
This process provides smooth surface,
against which the inner tube finds
little chance to buckle up or tear.
The tire is inspected not only after
it has been completed. At every stage
in the process of manufacture it comes
under he eyes of some inspector. The
slightest flaw is cause for it's being
turned aside for adjustment.
One unit of the Firestone factories
is devoted to the making of solid rub
Der truck tires exclusively. Here
special machines apply hard rub
Der to a steel rim as base. This is
roughened preparatory to the applica-
tion of tread rubber. The heavy tread
rubber is wrapped around each tire by
machinerv under very heauu $ens;on