Evening capital news. (Boise, Idaho) 1901-1927, 1917-02-04
Do You Know How Auto Tires
Are Made? hi. Article Tel. 4! Aeea. t

tic rubber into the fabric at h1gh pres
sure and impregnates it thoroughly
with the gum. The fabric for the
breaker strips and canvas plies Is first
held at great heat. in order to be
thoroughly dry. Then it is ready to be
wound into the calendars, which
friction" the rubber into the fabric.
There are three huge rolls on this
frictioning machine, the middle revolV-
ing at high speed and the lower at low
speed BY the difference in the speed
of the rolls the rubber is thoroughly
worked into the cloth, which winds on
one roll as the rubber revolves on the
drum opposite. Castings for automo-
bile tires are built up around mods
formed like wheel. Strips of the
heavily rubberiZed canvas OF varying
lengths, according to the circumference
of the tire to be built, form the flrbt
layer in the building up OF shoe.
These LAYERS have been sewed so that
they form a continuous piece ana then
are worked around the mold. AROUND
this inner layer go the various plies OF
canvas, until the breaker strip is'in-
serted. Plies of rubber are added Tor
the tread until the whole is built up in
the form that it is designed take.
This tire, mold and all. is carried
away to be weighed, because 1t must
come up to u certain standard. TINS
process. so briefly described, is one OF
the most important of all in tire build
ing. In the curing room, to which the
tire and mold go for the final step in
| the process. there is a part of the work
| in the factory which is its own special
device. 1t applies to the way in which
/ the casing is held in the shell before
il goes into the vulcanizer. Those tires
| which are designed to have wrapped
! tread 20 under a spiral machine which
winds narrow strip of canvas all
around the tread Then the castings
| are placed in the shells and out into
the curing ovens. where they remain
until the process is completed. In the
| mold the raised letters of the trade
! mark and the figures of the sizes are
embossed on them,
| In one room the big rubber biscuits
are crushed, washed and rolled into
! sheets. In the drying room the air
is constantly changed by huge cleo
trio fans. While the space shown
does not appear to be large, the pure
gum hung up to dry represents a
small fortune.
1 The most careful system Of inspec-
ton must be used in tire factory.
This Is especially true of the fabric.
The best tires contain the finest
grade of sea island cotton. 1t is i'm
Eportant that this fabric be carefully
dried, and this drying is so carefully
timed that no moisture remains to in
terfere with the perfect union of fab
81. f1,it
their natural oil for long life and ten
sle strength. In the calender rollers
the pure gum Is forced into every
thread of the fabric, and here again
the watchful inspector is ever on the
job.
The trade now demands the safety
tread, at least for the rear tires, and
many careful drivers use safety treads
for all four. The safety tread gives an
added wearing surface, which adds to
the life of the tire. If one wants to
go to the expense of buying the cord
tires they will get added value in ad-
ditional miles. The tire making is Il
definite system and workmen in the
manufactures are expert and compe-
tent. The tire may be sighted by a
poor quality of rubber or fabric, by
incompetent inspection in any depart
ment, by cutting down the number of
layers of fabric, by improper treat
ment OF the rubber compound, etc.
1t is on account of these facts that
manufacturers offer IA guarantee to
protect the purchaser against imper-
fcctions in manufacture. Tire makers
admit their responsibility does not end
with the sale of tire, and they are
united in trying to make good then
product even after it leaves their
hands. To get the best possible mile
age out of tire the user must CO.
, operate by the observance of simple
though important. regulations.