The Red Cloud chief., 1884-06-06
Diamonds fer Drills.

Diamonds are comparatively cheap
nowadays,' 4 rock drill manufacturer
said. and the diamond cit sets used in
the diamond drills do not cost as much
as they did,
Are genuine diamonds used in these
drills, or are they chatfcd diamond drills
because the steel has IN extremely hard
temper?:' the reporter asked.
diamonds are used in the drills.
They are chiefly one and two caret
stones. At present they cost about
twenty dollars a carct. They are in the
rough. The diamond-sct bit is hollow.
1t is a steel thimble. hayin" three rows
of diamonds embedded in it.. so that the
edges of those in n row project from
its face, while the edges of those in the
other two rows project from the inner
periphery respectively. The diamonds
of the first mentioned row cut the path
of the drill in its forward progress,
while those of the outer and inner
periphery of the tool enlarge the
cavity"
'.HOw are the diamonds set in the
bit?"
The bit is of soft steel. in which holes
are drilled. After the diamonds are
fitted the metal is hammered against
them so that they remain tirm.'
'.Do the diamonds veal out"
Their edges which come in contact
with the rock get a little smooth. and
they are taken out and reset. so that a
fresh edge is presented"
Have all the hollow drills three rows
of diamonds?"
mo. Some have only onc row but
these are not very largr. The diamonds
stand out from the Steel setting. 50 that
the steel does not come in cnn:act with
the rock"
''IIow are the diamond drills
wOrked?'
..By a rapid rotation varying any
where from four hundred to ono thou>-
and revolutions Il minute. There are
different machines u%ct for different
kinds of drilling. For deep boring a
Il machine with a double oscillating evil
indcr engine is used. mounted on an up
right or horizontal tubular boiler The
machine has L screw shalt made of
heavy hydraulic tubing from five to
seven feet in length. with Il deep screw
cut in the outside. The sh. # also ear
ries a spline. by which it is f"at!e;rd to
the lower sleeve gear. This gear is
double. and connects by lis upper teeth
with a bevelcd driving gear. and bv its
lower teeth with = release gear, which
is a friction gear. and is fitted
to the lower end of the shaft. to the
top of which Il gear is fcathcrcd. fitting
to the upper gear on the screw shaft.
which has one or more teeth less thar
the upper gear on the feed shaft. where
by a diffcrential feed is prodsce,l. Til.
friction gear is attached 10 the bottom
of the feed shaft by n friction nut. pro-
ducin@ a combined difIercntial and fric-
tional feed. which renders the drill per
fectly sensitive to the character of the
work tl.rDUs.. which il i: passing. and
maintaining Il uniform pr,.a,;r... The
drill rod. made of heavy llp-weld tub
ing. passes through the screw shaft and
is held firm by q chuck at the l.nttom of
the screw shaft. To the lower end of
this tuE ular boring rod the BIT is screwed.
and to the upper end is Il watch swivel.
t. which connection is made with Il
pump. You can SO BY this that
the machine is very simple AMI not
likely to get out of order.
The reporter fell into Il chair. When
he came to. the drill man was saving:
THE screw shaft. bc;nr rotated and
fed forward. roti!cS the dill roll and
bit. cutting an annular channel
where do You get the diamonds for
the bits?:' the reporter asked in dcSpcr-
alton.
They come principally from Brazil.
Some come from Siberia and SOME from
the South of Africa: the latter. how
ever, are mere CLASSY and are not 50
tough As the Brazilian diamonds. and
arc much more likely to crush under
preSSure."-N. y. Sun.