IMPROVEMENTS IN MACHINERY FOR CUTTING FILES
Year: 1858

page_text: LETTERS PATENT to Francis Preston, of the City of Manchester,
Mechanical Engineer, and William McGregor, of the same Place,
Mechanic, for the Invention of "IMPROVEMENTS IN MACHINERY FOR CUTTING
FILES."
Sealed the 1st February 1859, and dated the 20th August 1858.
PROVISIONAL SPECIFICATION left by the said Francis Preston and
William McGregor at the Office of the Commissioners of Patents, with
their Petition, on the 20th August 1858.
We, FRANCIS PRESTON, of the City of Manchester, Mechanical Engineer,
and WILLIAM MCGREGOR, of the same Place, Mechanic, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN MACHINERY FOR CUTTING
FILES," to be as follows:-
The first part of our Invention relates to the chisel holders of the cutting
machines, and consists in an improved mode of constructing the socket and
joint for the chisel holder in combination with a spring attached to the tail of
the chisel holder; also in supporting the chisel holder in a slide, so as to raise
the chisel in a line parallel to the cut, instead of in the are of a circle, as
heretofore; also in holding the chisel rigid between the jaws of a vice or
clamp forming the chisel holder, the chisel being held in its place in the vice
or clamp by a pin, key, or cotter; also in fixing the chisel rigidly to the chisel
holder by a bolt or screw, or bridle, and retaining the chisel in position by side
ribs or projections.
Secondly, in so constructing the cam for working the screw by which the

page_text: table is moved, that after the screw has been turned the necessary distance for
cutting a fresh tooth on the file, the action of the cam is continued, so as to
cause a slight pressure forward until after the fall of the hammer, to counteract
the tendency of the blow to loosen or reverse the screw, and thereby causing
the table to fall back and make irregular teeth.
Thirdly, the application of a friction clip or break to the screw by which the
table is moved, to assist in giving regularity to its movement.
Fourthly, the application of a loose weight or weights to the top of the
hammer, to prevent or diminish the vibration when the hammer falls; and
also the application of a spring to the tail or shaft of the hammer to effect the
same object.
And, lastly, the application of a break to stop the machine instantly when
the driving strap is thrown from the fast to the loose pulley.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Francis Preston and William McGregor in the Great Seal
Patent Office on the 19th February 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, FRANCIS
PRESTON, of the City of Manchester, Mechanical Engineer, and WILLIAM
MCGREGOR, of the same Place, Mechanic, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of August, in the year of our Lord
One thousand cight hundred and fifty-eight, in the twenty-second year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said Francis Preston and William McGregor, Her special licence that
we, the said Francis Preston and William McGregor, our executors, adminis-
trators, and assigns, or such others as we, the said Francis Preston and
William McGregor, our executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVE-
MENTS IN MACHINERY FOR CUTTING FILES," upon the condition (amongst others)
that we, the said Francis Preston and William McGregor, our executors or
administrators, by an instrument in writing under our or their, or one of our
or 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,

page_text: 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 we, the said Francis Preston and William
McGregor, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement (that is to say) :-
The nature of our Invention consists, first, in an improved mode of con
structing the socket and joint of the chisel holder in combination with a spring
applied to the tail of the chisel holder.
Secondly, in holding the chisel rigidly between the jaws of a vice or clamp
forming the chisel holder, the chisel being held in its place in the vice or
clamp by a pin, key, or cottar.
Thirdly, in so constructing the cam for working the screw, by which the
table is moved, that after the table has been moved the necessary distance
for cutting a fresh tooth, the action of the cam imparts a slight forward
pressure on the table until the blow of the hammer has been given.
Fourthly, in the application of a friction clip or break to the screw by
which the table is moved.
Fifthly, in the application of a loose weight or weights to the top of the
hammer.
And, sixthly, in supporting the chisel holder in a slide, in order that the
chisel may be raised off the file in a line parallel to the cut, instead of in the
arc of a circle, as heretofore customary.
And in order that our Invention may be fully understood and readily carried
into effect, we will proceed to describe the means pursued by us, reference
being had to the accompanying Sheet of Drawings, and to the figures and
letters marked thereon.
Figure 1 is an elevation of a file-cutting machine to which parts of our
improvements are applied; Figure 2 is a plan; and Figure 3 is an end view
of the same.
As this machine is somewhat similar to the one shewn in the Specification
of Letters Patent granted to us on the Fifteenth day of April, One thousand
eight hundred and fifty-eight, we have put corresponding letters of reference
upon all the parts that are alike in both machines.
a is a cast-iron bed, to which are cast or fixed the projections b, b, supporting
the standards c, c, which are united above by a bow c; the shaft & revolves in
bearings in the standards c, c; this shaft is provided with a fast and loose
pulley, shewn in Figures 2 and 3, and by a dotted circle in Figure 1; to this

page_text: shaft is fixed the cam e² for raising the hammer f, the cam for working the
screw a in the bed a, the cam for working the incline n, by which the chisel
is raised off the file, and the fly wheel e", by which the shaft d is turned by
hand when required. The table g moves on the bed a, and it is furnished
with a nut taking in the screw a', to which is fixed the ratchet wheel a²; the
lever is mounted loose on the end of the screw a', and has a click h³ taking
into the teeth of the ratchet wheel a; the lever h is moved up and down by
the came³, the peculiar shape of which will be explained hereafter. To the
bed a is fixed the upright j, supporting the adjustable plate j', to which is
bolted the slide k, the chisel holder k, swivels in the socket ke jointed to the
slide k, and the centre of this joint being below the level of the file, allows the
chisel or cutter to rise freely out of the cut. The chisel holder is acted upon
by the spring m, which is coiled round the shank, and presses against the
button at the end of the shank, and against the socket, thereby allowing the
chisel holder to swivel, and the chisel 7 to adjust itself to the face of the file,
or the spring m may be applied in the manner shewn in the Specification
above referred to; the spring k presses the chisel holder down after it has
been raised by the incline n, which is fixed to the rod n¹ jointed to the lever n²,
to which is connected a bowl acted upon by the came above referred to.
Our improved chisel holder is shewn best in Figures 4, 5, and 6, which
represent a side view, a plan, and an end view of the same; the chisel holder
is similar to a clamp, which is held closed by the bolt ; the chisel is
securely held when the bolt is tightened, and it is also held in the holder by
the pink, or by a key or cottar. When it is necessary to remove the chisel
from the holder, the bolt 8 is loosened, and the jaws of the clamp are opened,
as shewn by dotted lines in Figure 5; the jaws may also be jointed together
like a hand vice; but the clamp shewn in the Drawing is found the most
convenient in practice.
The third and fourth of our improvements refer to the mechanism for giving
motion to the table g; the cam fixed on the shaft e acts on the lever e',
which is connected by the link h¹ to the lever h, for giving motion to the
screw a', and it is made slightly eccentric between the points x and y, so that
when the lever et has been moved sufficiently to make the catch h² advance
the ratchet wheel a for a tooth; the eccentric portion of the cam imparts a
slight forward pressure to the table until the hammer f has fallen on the chisel
to cut the tooth in the file, by this means the tendency of the blow to loosen
or reverse the motion of the screw is counteracted, and more regularity in the
teeth of the file is obtained; the table g is also acted upon by a weight
attached to a chain passing over a guide pulley in the ordinary manner.
The

page_text: screw a' is provided with a friction clip or break marked as in Figure 2, and
in the detached view Figure 7; the two halves of this clip are lined with
leather, or other suitable material, and are tightened together by screw bolts,
so as to give the required amount of friction, the object being to prevent the
screw moving, except when the ratchet wheel a is acted upon by the
cam e³
The fifth of our improvements has reference to the hammer for striking the
chisel; when the hammer is constructed in the usual manner, it is very liable
to rebound or vibrate after the blow has been given; in order to prevent or
diminish this, we apply one or more metal washers or loose weights marked f³;
to the top of the hammer, as shewn in Figure 1; these metal washers or loose
weights are separated from each other and from the head of the hammer by
washers of leather, or other suitable material.
When the machine is set to work, the end A of the file blank is brought
under the chisel, and as soon as the highest point of the cam e has got beyond -
the bowl on the adjustable picce f³, the hammer f drops on the head of the
chisel, thereby cutting the first tooth, the chisel is then raised by the incline n
which is pushed under the stud projecting from the chisel holder in the
ordinary manner; the table g is then moved the requisite distance for cutting
a fresh tooth in the file, by the cam giving motion to the ratchet wheel a²;
the incline n is then withdrawn from under the stud of the chisel holder, and
the spring brings the chisel again on to the face of the file, ready to receive
the next blow of the hammer; these operations are repeated until the whole
surface of the file has been cut, when, by means of a self-acting stop motion of
the usual construction, which is not shewn in the Drawing, the driving strap
is moved from the fast to the loose pulley, thereby stopping the machine; the
attendant then turns round the wheel a gearing into the pinion a³ fixed to the
screw a', to bring the table back to its original position, and after reversing
the position of the file, or replacing it with another file blank, the machine is
again set in operation by bringing the driving strap on to the fast pulley.
In Figures 8, 9, and 10, we have shewn the mode of constructing our last
improvement in file-cutting machines; the chisel holder v, instead of swivelling
in a piece which is jointed to a horizontal slide k, as described in reference to
the foregoing figures, is made to swivel in the slide v', which fits between a
V-groove in the angle slide ; this slide v¹ moves in a line parallel or nearly
parallel to the cut of the chisel, consequently when the incline n is pushed
under the projection to raise the chisel off the file, the chisel moves in a
line parallel to the cut, instead of in the arc of a circle, as heretofore. The
spring is to press the slide v down again after it has been raised by the

page_text: incline n. The chisel fits between projections on the chisel holder, and it
is held rigidly in its place by the bridle v', which is held by screws, as shewn
in the Drawing, or by bolts; or the chisel may be connected to the chisel
holder in any other convenient manner.
Having thus stated the nature of our Invention, and described the manner
of performing the same, we wish to remark, that we do not confine ourselves
to the details given, as the same may be modified without departing from the
peculiar character thereof; we also wish it to be understood that we make no
claim to those parts of the file-cutting machine which we have shown and
described to illustrate our present improvements, and which are either old or
were secured to us by the Letters Patent above referred to; but we limit our
claims to the following parts, namely:-
First, the improved socket and joint for the chisel holder, shewn and
described in reference to Figures 1, 2, and 3, in combination with the
spring m.
Secondly, the holding of the chisel rigidly between the jaws of a vice or
clamp, as shewn and described in reference to Figures 1, 2, 4, 5, and 6, and
combining therewith a pin, key, or cottar, for holding the chisel in its place.
Thirdly, making the cam for working the screw of the table eccentric, for
the purpose described in reference to Figure 1.
Fourthly, the application of a friction clip to the screw, by which the table
is moved, as shown and described in reference to Figures 2 and 7.
Fifthly, the application of metal washers or loose weights to the hammer,
to prevent or diminish the rebound or vibration thereof, as shewn and described
in reference to Figure 1.
And, sixthly, in supporting the chisel holder in a slide, in order that the
chisel may be raised off the file in a line parallel to the cut, as shown in
Figures 8, 9, and 10.
In witness whereof, we, the said Francis Preston and William McGregor,
have hereunto set our hands and seals, this Eighteenth day of
February, in the year of our Lord One thousand eight hundred and
fifty-nine.