IMPROVEMENTS IN TOOLS AND FITTINGS OF DRILLING AND BORING APPARATUS
Year: 1877

page_text: LETTERS PATENT to Julius Hall, of 90, Chancery Lane, for the Invention
of "IMPROVEMENTS IN TOOLS AND FITTINGS OF DRILLING AND BORING
APPARATUS."
Sealed the 19th February 1878, and dated the 28th December 1877.
PROVISIONAL SPECIFICATION left by the said Julius Hall at the Office of
the Commissioners of Patents on the 28th December 1877.
JULIUS HALL, of 90, Chancery Lane.
OF DRILLING AND BORING APPARATUS.'
"
"s
IMPROVEMENTS IN TOOLS AND FITTINGS
This Invention relates to the drilling of square holes, or modifications of the
same, in metals or other substances by rotary motion at one operation, thereby
superseding the present method of making such holes, which is usually done by
first drilling out circular holes and then cutting or filing them until they assume a
square frame.
For this purpose I employ a three-sided drill, (such three-sided drill
can either be flat or fluted,) which in cross section is of the form of an equilateral
triangle.
I make the bottom or cutting edges of the drill perfectly flat and three in
number, each cutting edge extending from one of the outer corners to the centre of
the triangle.
My method of using such drills in an ordinary vertical drilling machine is as
follows-I provide a special drill chuck, which forms part of my Invention, and
which I attach to the lower end of the drilling spindle. The chuck is constructed
in such manner as to admit of the drill travelling automatically in a horizontal
plane some little distance. This is rendered necessary by the peculiar movement
of the cutting edges of the drill, which does not operate or rotate on a fixed central
point, but diverges somewhat therefrom in proportion to the size of the hole.
Near to the lower end or cutting edges of the drill I fix rigidly a metal guide
bar or plate. The guide bar is provided with a square hole similar to the hole it is
required to drill, the dimensions of the three sides of the drill being such that the
Prin 21

page_text: distance from the base to the apex of the triangle, which such three sides form, is
the same as one of the sides of the square hole it is required to drill.
I prefer to make the guide bar of steel, which I harden at that part where the
guide hole is made. The method of operation is then as follows:-The three-sided
drill being fixed in the self-adjusting chuck, the guide bar with the square guide
hole therein rigidly fixed above the point where it is required to drill, the drilling
spindle carrying the chuck and drill is made to revolve and screwed or pressed
downwards, upon which the drill works downwards through the square guide hole,
and drills holes similar in size and form to this latter.
Another method employed by me, and forming part of my Invention, is not to
fix the guide bar to the machine but on to the substance or work to be drilled, in
which case the drill operates equally well; but this plan necessitates frequent
removal and refixing of the guide bar.
My triangular drill for drilling square holes may also be used without the self-
adjusting drill chuck, and in any ordinary chuck when the substance operated upon
is not very heavy; as then, instead of the lateral movement of the drill, such lateral
movement will be communicated by the drill to the substance operated upon.
Although I have only cited the case of a vertical drilling machine in connection
with this Invention, I have to remark that the above specified improvements are
equally applicable to lathes, ratchet braces, and all other descriptions of drilling
apparatus.
The modification of square holes above alluded to are made by rounding off the
corners of the triangular drill, by which the corners of the square hole are also
rounded off.
In the case of an ordinary vertical drilling machine I construct my drill chuck,
which has for its object the automatic lateral motion of the drill, in the following
manner: I make a hollow metal cylinder, the upper part of the cavity of which
is bored out circularly, so as to fit on to the drilling spindle, to which it is screwed
by one or more screws or other attachments. Below the circular bore a square
recess is made, and below this latter, and coming well within the limits of the
square recess, there is a circular hole passing through the end of the cylinder.
I make in a separate piece the drill holder or socket, the bottom portion of
which I provide with a square or round recess for holding the shank or upper end
of the drill, which is held firmly in its place by means of a set screw or other
appliance. The upper part consists, first, of a screw at the top; secondly, of a
square shoulder; thirdly, of a circular shoulder; and fourthly, of another but much
larger circular shoulder. I insert through the circular hole at the bottom of the
hollow cylinder the upper portion of the drill holder until the large circular
shoulder meets the bottom of such cylinder. I then place a loose square collar,
provided with an oblong rectangular slot, within the cylinder and over the square
shoulder above mentioned, above and on to which I screw down a nut from the
inside of the cylinder. The loose square collar is of such thickness that when the
nut is tightened down on to the square shoulder the loose collar is left to work
freely. When this is done the drill holder will readily travel in a horizontal plane
such distance as the play between two of the sides of the loose collar and two of the
sides of the square recess in one direction, and in another direction the distance
that the play between two of the sides of the small square shoulder on the drill
holder and the ends of the rectangular slot in the loose collar. The horizontal
travel or play is proportionate to the size of the hole to be drilled.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Julius Hall in the Great Seal Patent Office on the 19th June
1878.
JULIUS HALL, of 90, Chancery Lane.
OF DRILLING AND BORING APPARATUS."
"IMPROVEMENTS IN TOOLS AND FITTINGS
This Invention relates to the drilling of dead square holes, square holes, or
modifications of the same, in metals or other substances by rotary motion at one
operation, thereby superseding the present method of making such holes, which is
usually done by first drilling out circular holes, then cutting or filing them until
they assume a square form. For this purpose I employ a three-sided drill (such
three-sided drill can either be flat or fluted), which in cross section is of the form
of an equilateral triangle.
I make the bottom or cutting edges of the drill perfectly flat and three in
Dumber, each cutting edge extending from one of the outer corners to the centre of
the triangle.
My method of using such drills in an ordinary vertical drilling machine is as
follows: I provide a special drill chuck, which forms part of my Invention, and
which I attach to the lower end of the drilling spindle. The chuck is constructed
in such manner as to admit of the drill travelling automatically in a horizontal
plane some little distance. This is rendered necessary by the peculiar movement
of the cutting edges of the drill, which does not operate or rotate on a fixed central
point but diverges somewhat therefrom in proportion to the size of the hole.
I construct my drill chuck, which has for its object the automatic lateral motion
of the drill, in the following manner:-I make a hollow metal cylinder, the upper
part of the cavity of which is bored out circularly, so as to fit on to the drilling
spindle, to which it is screwed by one or more screws or other attachments. Below
the circular bore a square recess is made, and below this latter, and coming well
within the limits of the square recess, there is a circular hole passing through the
end of the cylinder.
I make in a separate piece the drill holder or socket, the bottom portion of which
I provide with a square or round recess for holding the shanks or upper end of the
drill, which is held firmly in its place by means of a set screw or other appliance.
The upper part consists, first, of a screw at the top; secondly, of a square shoulder;
thirdly, of a circular shoulder; and fourthly, of another but much larger circular
shoulder. I insert through the circular hole at the bottom of the hollow cylinder
the upper portion of the drill holder until the large circular shoulder meets the
bottom of such cylinder; I then place a loose square collar provided with an oblong
rectangular slot within the cylinder and over the square above mentioned, above
and on to which I screw down a nut from the inside of the cylinder. The loose
square is of such thickness that when the nut is tightened down on to the square
shoulder the loose collar is left to work freely. When this is done the drill holder
will readily travel in a horizontal plane such distance as the play between two of
the sides of the loose collar and two of the sides of the square recess in one
direction, and in another direction the distance that the play between two of the
sides of the small square shoulder of the drill holder and the ends of the rectangular
slot in the loose collar. The horizontal travel or play is proportionate to the size
of the hole to be drilled.
Near to the lower end or cutting edges of the drill I fix rigidly a metal guide bar
or plate. The guide bar is provided with a square hole similar to the hole it is
required to drill, the dimensions of the three sides of the drill being such that the
distance from the base to the apex of the triangle, which such three sides form, is
the same as of the sides of the square hole it is required to drill.
I prefer to make the guide bar of steel, which I harden at that part where the
guide hole is made. The method of operation is then as follows:-The three-sided

page_text: drill being fixed in the self-adjusting chuck, the guide bar with the square guide
hole therein rigidly fixed above the point where it is required to drill, the drilling
spindle carrying the chuck drill is made to revolve and screwed or pressed down-
wards, upon which the drill works downwards through the square guide hole, and
drill holes similar in size and form to this latter.
Another method employed by me and forming part of my Invention is not to fix
the guide bar to the machine but on to the substance or work to be drilled, in
which case the drill operates equally well; but this plan necessitates frequent
removal and refixing of the guide bar.
My triangular drill for drilling dead square holes and holes may also be used
without the self-adjusting drill chuck in any ordinary chuck, when the substance
operated upon is not very heavy nor stationary, then instead of the lateral move-
ment of the drill such lateral movement will be communicated by the drill to the
substance operated upon.
Although I have only cited the case of a vertical drilling machine in connection
with this Invention I have to remark that the specified improvements are equally
applicable to lathe, ordinary braces, ratchet braces, and all other descriptions of
drilling apparatus.
The modifications of square holes above alluded to are made by rounding off the
corners of the triangular drill, by which the corners of the square holes are also
rounded off.
In making oblong dead square cornered holes or holes, either the substance to be
operated upon must be allowed to move in one direction more than another, or by
having the hole in the guide plate made to the shape required, and my drill chuck
made to give the drill greater play in one direction.
In order that my Invention may be readily understood I have annexed hereto a
Sheet of Drawings, where Figure 1 shews a vertical section of my improved chuck,
in which a is the hollow cylinder, which may be attached to any ordinary drilling
machine; b is the drill holder; b' is a screw; 62 is a square shoulder; 6³ is a
circular shoulder; b is a circular shoulder of a larger dimension; c is a screw nut
for tightening on to the square shoulder 6³; and d, the loose square collar.
Figure 2 is a plan view of Figure 1.
Figure 3 is an elevation of my improved chuck; e, the three-sided drill and
guide barf complete.
Figure 4 is a plan of the guide bar f, shewing the three-sided drill e in cross
section.
Having now described the nature of my Invention and the manner in which the
saune is to be performed, I wish it to be understood that I do not limit myself
to the precise details herein-before described, as the same may be varied without
departing from the nature or principle of my said Invention; but I claim as my
said Invention,---
Firstly. The employment of a rotary motion for the purpose of drilling or
boring square holes and modifications of square holes.
Secondly. The chuck.
Thirdly. The three-sided drill.
And, Fourthly. The guide bar, as substantially herein described, and as illustrated,
or any mere variation or modification thereof.
In witness whereof, I, the said Julius Hall, have hereunto set my hand
and seal, this 19th day of June, in the year of our Lord One thousand eight
hundred and seventy-eight.
JULIUS HALL. (L.B.)