AN IMPROVED DRILL FOR BORING OR PERFORATING ROCKS OR OTHER LIKE SUBSTANCES
Year: 1877

page_text: LETTERS PATENT to William Wallace Dunn, of San Francisco, California,
United States of America, now of 8, Southampton Buildings, London, Engineer,
for the Invention of "AN IMPROVED DRILL FOR BORING OR PERFORATING
ROCKS OR OTHER LIKE SUBSTANCES."
Sealed the 13th October 1877, and dated the 16th April 1877.
PROVISIONAL SPECIFICATION left by the said William Wallace Dunn at
the Office of the Commissioners of Patents on the 16th April 1877.
WILLIAM WALLACE DUNN, of San Francisco, California, United States of America,
"AN IMPROVED DRILL FOR
now of 8, Southampton Buildings, London, Engineer.
BORING OR PERFORATING ROCKS OR OTHER LIKE SUBSTANCES."
This Invention relates to an improved drill for boring or porforating rocks or
other like substances, and is designed to overcome certain difficulties which exist.
with drills as heretofore constructed and used for the above purposes.
It is well known that with these drills, as hitherto used, there is when they are
in operation considerable wear upon their cutting points and edges, and the said
edges wear away so rapidly that the diameter of the drill end becomes diminished
to such an extent as to cause the hole being drilled to diminish to a corresponding
degree, and thus the work done within a given time is materially affected. In practise
it is found that the drill edges wear away, to such an extent as to reduce the diameter
of the hole from 1/1 to 1/8 inch for every foot bored, more or less, according to the
nature of the rock.
16
Another disadvantage attending the use of the drills for boring rocks, as here-
tofore constructed, is that when a seam is encountered the drill frequently will not
operate, and considerable delay is the consequence, and the hole commenced has
sometimes to be abandoned.
'
My said Invention is designed to remedy the aforesaid difficulties, and I have
found that a drill end constructed as herein-after described has the desired effect,
and is capable of doing fifty per cent. more work within a given time than any
other known drill used for boring or perforating rocks.
In carrying my said Invention into practise I construct the drill end with wings
or projections extending backwards longitudinally from the cutting edges in such a

page_text: manner that the said wings or projections form a support against the rock or other
material being operated upon, and serve also as a guide. This construction has the
effect of keeping the drill end in a straight line in forming a hole, and the said hole
will be perfectly round throughout its entire depth.
The said wings or projections may be of any desired length and thickness, and
they will correspond in number with the cutting points or edges, of which they may
be called continuations.
The spaces or channels between the said wings or projections are sufficiently
large to allow the debris or fragments of rock or other material to pass through
thein out of the hole. The drill may have two, three, four, or more cutting edges
and wings.
The said improved drills may be made of various sizes, and may be applied to
any drilling machinery or apparatus used for boring or perforating rocks and other
like materials.
•
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Wallace Dunn in the Great Seal Patent Office on the 15th
October 1877.
WILLIAM WALLACE DUNN, of San Francisco, California, United States of America,
"AN IMPROVED DRILL FOR
now of 8, Southampton Buildings, London, Engineer.
BORING OR PERFORATING ROCKS OR OTHER LIKE SUBSTANCES."
This Invention relates to an improved drill for boring or perforating rocks
or other like substances, and is designed to overcome certain difficulties which
exist with the drills or implements heretofore constructed, and used for the above
purposes.
It is well known that with the drills or implements hitherto used for such
purposes there is when they are in operation considerable wear upon their cutting
points or edges, and the said edges wear away rapidly, and the diameter of the drill
end is thereby diminished to such an extent that the hole being drilled will as the
work proceeds diminish in diameter, and thus the useful effect obtained within a
given time and with a given expenditure of power is considerably less than it
should be. In practice it is found that the drilled edges wear away to such_an
extent as to reduce the diameter of the hole from 1/10 to 1 inch for every foot
length of the hole bored, this amount being more or less, according to the nature or
quality of the rock.
Another disadvantage attending the use of the drills for boring rocks, as here-
tofore constructed, is that when a seam is encountered the drill frequently will not
operate, and considerable delay is the consequence, and the hole commenced some-
times has to be abandoned.
My said Invention is designed to remedy the aforesaid difficulties, and I have
found that a drill constructed as herein-after described will operate very effectually
and advantageously, that is to say, with this improved drill fifty per cent. more
work may be done within a given time than with any other known drill or
implement used for boring or perforating rocks.
In carrying my said Invention into practice I construct the drill as shewn in the
accompanying Drawing, in which,-
Figure 1 is a view of the nose or point of the drill, and Figures 2 and 3 are side
views of the same, at right angles to each other.
Like letters indicate the same parts throughout the Drawing.
The said drill has wings or projections at extending backwards longitudinally from
the cutting edges b in such a manner that the said wings or projections form a
support against the rock or other material being operated upon, and serve also as a
guide. This construction has the effect of keeping the drill end in a straight line in
forming a hole, and the said hole will be truly round throughout its entire depth.

page_text: The said wings or projections a may be of any desired length and thickness, and
they will correspond in number with the cutting points or edges b, of which they
inay be called continuations. The said wings are made a little taper, with an
inward inclination backwards from the points b, as shown, to avoid any binding of
their surfaces against the surface of the hole, which might otherwise occur.
The spaces or channels c between the said wings or projections are sufficiently
large to allow the debris or fragments of rock or other material to pass through
them out of the hole. The drill may have two, three, four, or more cutting edges
and wings.
The said improved drills may be made of any desired sizes, and may be applied to
any drilling machinery or apparatus used for boring or perforating rocks and other
like materials.
Having thus fully described the said Invention, and the manner of performing
the same, I wish it understood that I claim, a drill or implement for boring or
perforating rocks or other like substances, and which is constructed with wings or
projections extending, backward from its cutting edges, and serving to support and
guide the said drill, as above set forth.
In witness whereof, I, the said William Wallace Dunn, have hereunto set my
hand and seal, this Thirteenth day of October, in the year of our Lord One
thousand eight hundred and seventy-seven.
WILLIAM WALLACE DUNN. (L.S.)