IMPROVE- MENTS IN DRILLS FOR BORING HOLES
Year: 1873

page_text: LETTERS PATENT to Charles Julius Ball, of New Bridge Street,
Blackfriars, in the City of London, for the Invention of "IMPROVE-
MENTS IN DRILLS FOR BORING HOLES."
Sealed the 4th November 1878, and dated the 6th May 1873.
PROVISIONAL SPECIFICATION left by the said Charles Julius Ball
at the Office of the Commissioners of Patents, with his Petition,
on the 6th May 1873.
I, CHARLES JULIUS BALL, of New Bridge Street, Blackfriars, in the
City of London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN DRILLS FOR BORING HOLES," to be as follows:-
My improvements relate to improvements in the shape and methed of
manufacture of drills used for the purpose of boring holes in metal,
rock, or other hard substances, and they are especially applicable to drills
actuated by boring engines in which the drills have a reciprocating.
longitudinal motion imparted to them by means of steam, compressed
air, or other fluid.

page_text: I make the drill consist of a bar, preferably circular in cross section,
and having its cutting extremity circular, but of somewhat greater
diameter than the remainder, and made hollow so as to be annular in
shape in end view, and I form the cutting end of this annular part into
two or more angular teeth, the plane of the cutting faces of which may
be made either radial or more or less tangential to the circumference of
the drill. By this arrangement of the form of the drill less power is
required to work it, and the hole is made more truly circular in form
than where drills of the shape ordinarily used are employed.
Sometimes I form teeth upon the annular face which forms the cutting:
face of the drill as follows:-I divide the face into two or more divisions,
and I make one of these divisions into a tooth, the cutting edge of
which is radial or nearly so with the centre of the drill. The next
division I make into a tooth having two cutting edges parallel or nearly
so with the circumference of the drill, one of these cutting edges being :
formed upon
the outer circumference of the annular face, and the other
cutting edge being formed upon its inner circumference, the space
between the two edges forming a depressed angle. Sometimes I use to
this tooth one cutting edge only, which may be upon its outer or inner
circumference or between the two. The third division (if more than
two are used) I make into a similar tooth to that in the first division,
and the fourth division into a tooth similar to that in the third, and so
on alternately, until the whole annular face is filled with teeth. By this
method of construction the ring of rock or other substance which is
being cut is first chipped by a radial tooth, then by a circumferential
tooth, and so on alternately, and in this way it is cut moro easily and
with greater speed than is usually the case.
In order to make the cutting part of the drill I take a suitable bar of
steel, or steeled at its end, tubular for a sufficient part of its length, and
I increase its diameter and form the teeth described at its extremity by :
pressing, hammering, or forging it in suitable moulds or swages, and I
sharpen the teeth when necessary by hammering or filing them.
By using drills formed according to my Invention an annular ring
only has to be cut in the rock or other hard substance, and the central
core either remains in the hollow of the drill or it becomes broken up
and discharged from the hole with the other débris round the drill.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Charles Julius Ball in the Great Scal Patent
Office on the 6th November 1878.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
JULIUS BALL, of New Bridgo Street, Blackfriars, in the City of London,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of May, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Charles Julius Ball, Her special licence
that I, the said Charles Julius Ball, my executors, administrators,
and assigns, or such others as I, the said Charles Július Ball, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "Im-
PROVEMENTS IN DRILLS FOR BORING HOLES," upon the condition (amongst
others) that I, the said Charles Julius Ball, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of
the said Letters Patent.
NOW KNOW YE, that I, the said Charles Julius Ball, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement and accompanying Drawing (that is to
say):-
My Invention relates to improvements in the shape and in the method
of manufacture of drills used for boring holes in rock, metal, or other
hard substances, which improvements are especially applicable to drills
actuated by boring engines in which the drills have
A

page_text: motion imparted to them by steam, compressed air, or other fluid, whilst
they are at the same time caused to rotate gradually.
In order to construct such drills of an improved shape according to
my Invention I take a bar of iron or steel, or of iron steeled at its end,
or of any other suitable material, and of any suitable size and cross b
section, but preferably circular or polygonal in section, and having its.
cutting extremity circular in end view, but of a diameter somewhat
greater than the remainder of the bar, and made hollow so as to be
tubular or annular in end view, and I form the cutting end or extremity
of this annular part into two or more angular teeth, the plane of the 1
cutting face of which may be made either radial or at an angle more or
less tangential to the circumference of the annular part of the drill. I
make the cylindrical hole in the tubular part of the drill of somewhat
less diameter at the outer or cutting end than in the remainder of its
length. By this arrangement of the shape of the drill less power is
required to work it, and the hole bored is made more truly circular in
form than where drills are employed of the shape ordinarily constructed
and used.
Sometimes I form the teeth upon the annular surface which forms the
cutting face of the drill, as above described, as follows:-I divide the
face into two or more divisions in end view, and I make one of these
divisions into a tooth, the cutting edge of which is radial or nearly so
with the centre of the drill. The next division I make into a tooth
having two cutting edges parallel or nearly so with the circumference of
the drill, one of these cutting edges being formed upon the outer circum-
ference of the annular face, and the other cutting edge being formed
upon its inner circumference, the space between the two forming a
depressed angle in transverse section across the tooth. Sometimes I use
for this tooth one cutting edge only, which may be upon its outer or
inner circumference or between the two. The third division (where
more than two are used) I make into a similar tooth to that in the first
division, and the fourth division into a similar tooth to that in the second,
and so on alternately, until the whole annular space is filled with teeth as
many in number as may be required.
Another form in which I sometimes make the annular cutting face of
the drill consists of a star-shaped series of angular teeth (in end view),
or instead of such angular teeth I sometimes make both the exterior and

page_text: interior angles join each other by curved lines, so that the cutting edge in
end view forms a waved line running round the annular face of the drill.
By the methods of construction described a ring of rock (or other
substance which is being cut) is chipped first by a tooth or part of a
tooth, more or less radial, then (as the drill rotates) by a tooth or part of
a tooth, more or less circumferential, and so on alternately, and in this
way it is cut more easily and with greater speed than is the case in drills
for such purposes as ordinarily constructed and used, as an annular ring
only has to be cut in the rock or other hard substance, the central core
of which either remains in the tubular part of the drill or becomes
broken up and discharged from the hole with the other débris round the
drill.
In order to form the teeth as above described upon the annular face
of the drill I either cut the teeth separately upon the steel face of the
bar formed as above described, or I form them by pressing, hammering,
or forging the face when hot in suitable moulds or swages, and I then
harden them, and I sharpen them when necessary by reforging or
pressing, or by hammering or filing them.
The accompanying Drawing is in illustration of my Invention:-
Figure 1 is a longitudinal section, and Figure 2 in end view of a
tubular drill before the teeth have been formed upon its cutting face.
a is the tubular body of the drill; 6 is the annular cutting face, the
outer diameter of which is larger than that of the tube a and its inner
diameter less than that of the tubular hole.
Figures 3 and 4 shew end and side views of angular radial teeth
formed upon the annular face.
Figures 5 and 6 shew end and side views of angular teeth, alternately
radial and circumferential, formed upon the annular surface.
Figure 7 shews an end view of angular teeth, the inner angles of
which are formed at the inner circumference of the cutting face and the
outer angles at its outer circumference.
Figure 8 shews the teeth last described joined together by curves
instead of angles, so that in end view their edge upon the annular face
appears as a continuous waved line.

page_text: Having now described my Invention, and the manner in which it is
to be performed, I claim, the construction of tubular drills having
expanded annular faces, upon which cutting teeth are formed, substan-
tially as described and shewn in the Drawing.
In witness whereof, I, the said Charles Julius Ball, have here.
unto set my hand and seal, this Sixth day of November, in
the year of our Lord One thousand eight hundred and seventy-
three.
CHARLES JULIUS BALL. (L.S.)