The Hawaiian star. [volume] (Honolulu [Oahu]) 1893-1912, 1897-02-05
THE STEEL BALLS.
They Are Ground, and Ono Firm Make
100000 Month.


100000 n Month.
Ball bearings became famous when
they were put in bicycles. But ball bear
ings were in use before the safety BIZ
cycle was invented, and they are used
so extensively as friction killers in ma
chinery of all sorts that one single fac
tory of the three which make the little,
turns out l6, 900, 600 balls every month.
Of course the balls are made by ma
Chinery A skilled lathe hand can turn
out perfect metal sphere. but if every
one of the little balls which enable a
bicycle wheel to turn so easily was made
by hand the cost would send the price
of bicycles up sky high The machinery
which makes ball bearings is called au-
tomato, but the abrasive material used
to grind the steel balls wears away, and
hence it is necessary for the operator to
feed" the grinding wheel up to the
work, so that the machinery is not alto
gether automatic. In making a complete
steel ball the first "blank'' is either
forged out of steel bar with steam
hammer or is turned out by an automatic
screw machine, leaving the blank in the
shape of a roughly shaped sphere, with
two little nibs, one opposite the other.
In this form it, with numerous others
like it, is fed into the rough grinding
machine, where it is started OH its way
toward the perfect sphere. No attempt
is made to cut off the little necks or
nibs before the blank is fed into the ma
chine, for the grinding stone soon eats
them away.
The principal part Of the rough grind
ing machine consists of "holding
down" ring, which keeps the balls in
the V shaped channel which runs around
the groove disk. Below the ring is the
grinding wheel, which is so supported
that it can be "fed" up to the work by
the most delicate kind Of feeding de.
vice and is so arranged that the balls
travel over the entire face of the wheel.
After the rough balls are placed in the
machine the top ring is put down or
them, the grinding wheel is fed up tC
touch the balls, and the grinding begins
At first the sparks come in splits and
flashes, but soon there is steady stream
of fire, whirling like ring of sparks,
which indicates that the balls have beer
ground to spheres.
The machine then is stopped, and the
balls are taken out and measured by {
micrometer gauge. The rough grinding
is continued until the balls have beer
ground down to the required size, which
is within one-thousandth inch of thu
polished and finished ball. The rough
balls are taken to the inspectors table
where they are examined for imperfec
tions. Each inspector uses a shallow
tray made of pine and finished witt
shellac varnish. Enough balls are placed
in the tray to cover two-thirds of tn,
| bottom.
The inspector gives his tray twis
and a turn, which changes the position
of every ball and brings them all VI
close together. Then he holds the ira,
in such position that the light reflect
from them. If the balls are round, Their,
is ring of reflected light from each on
of them, but any imperfection in tn
form of ball distorts the reflection ant
thus betrays the imperfect ball. Such j
lifted from the tray with magnetizet
steel pencil, and the selection is carried
on until none but perfect balls remain
in the tray.
The perfect balls then 60 to the pol
ishing machine, where they are polishe
with oil and fine emery, and every fey
minutes the operator stops the machin
to measure samples of the balls, an
this is kept up until the polished ball
are of the exact size required.
The next step in the process is to hard
en- the balls. They first are heated j.
an iron vessel. which is constantly KEEP
in motion, so that the balls will be even
ly heated. When the proper tempera
ture has been reached, the balls are sue
denly dropped into oil and thus receiv
the temper which makes them hard.
The hardened balls are next placed j
an oaken tumbler barrel, where the
are tumbled around and up against eac
other until each ball is FURNISHED unit
it looks like globule Of mercury. The
they are inspected, measured and sorted
the measuring and asserting being don
by very ingenious automatic machinery
Balls are made from one-eighth inc
in diameter to five inches in diameter
the latter for use in pump valves. Mos
of the balls made for ball bearings al
used in bicycles, but millions of thel
60 into sewing machines and in othe
machinery where it is desirable to n
duce friction to minimum. America
Machinist.