IMPROVEMENTS IN CUTTING WOOD
Year: 1855

page_text: LETTERS PATENT to George Tomlinson Bousfield, of 8, Sussex Place,
Loughborough Road, Brixton, in the County of Surrey, for the Inven-
tion of "IMPROVEMENTS IN CUTTING WOOD."-A communication.
PROVISIONAL SPECIFICATION left by the said George Tomlinson Bousfield
at the Office of the Commissioners of Patents, with his Petition, on the
24th July 1855.
I, GEORGE TOMLINSON BOUSFIELD, of 8, Sussex Place, Loughborough Road,
Brixton, in the County of Surrey, do hereby declare the nature of the Inven-
tion for "IMPROVEMENTS IN CUTTING WOOD" to be as follows:-
The Invention consists in bringing into action upon the opposite sides of a
mortise a series of cutting edges, each of which enters into the wood deeper than
the one preceding it by the difference created by the diverging line in which
the cutting edges are set. The tool by which the Invention is carried into
practice is composed of a wedge of cast steel, the point of which is as broad as
its width, thus forming a square, and whose thickness is uniform and as great
as the width of the mortise proposed to be cut by it. Its opposite diverging
sides terminate in parallel lines at the upper end of the width required for the
mortise. The diverging opposite edges are then cut into a series of teeth,
similar somewhat to the teeth of a heavy saw, leaving between the gullets a
chisel of sufficient strength to bear the pressure required in driving the tool

page_text: through the wood. This will vary with the size of the tool, and may be stated
to range between /gth of an inch to 1 inches. The gullet must be of sufficient
depth to contain the chips cut by the chisel above it during its passage
through the mortise, and should be about three times as deep as the width of
the chisel. The angle of divergence between the opposite cutters ought to be
such as to take off only about the /soth of an inch to each chisel when working
in hard wood, but this may vary with the material.
In using this tool it may be used by hand with a mallet, or it may be fixed
to an ordinary drop hammer working in slides, so as to insure its falling in
the same place every time. This latter is the true method where the tool is
to be worked for a large operation. A hole is to be bored into the piece of
wood to be mortised in the centre of the parallelogram desired to be cut out,
whose diameter is the same as the width of the mortise. The piece is then
laid on a bench having a mortise hole in it of the. size sufficient to allow the
passage of the tool; the tool is then applied with its lower end to the round
hole, and is driven through by the force of the weight, or by any power which
may be convenient. Each chisel cuts a shaving of the thickness which its
edge overreaches, the chisel preceding it, and the chips are collected in the
gullet, and carried in it till it passes through the hole, when they fall out.
The first cutter squares the round hole, and all the succeeding ones mearly
widen it.
It is apparent that the opposite edges of this tool may be made to move
relatively to each other by a hinge at or near their point of greatest proximity,
so as to make the same tool adjustible to different widths of mortises; and it is
also apparent that the teeth may be set on four sides of a square or triangular
tool to cut any shaped hole, and that two or more may be laid side and side,
so as to cut holes of different widths, while the principle would remain the
same, and that the tool may be actuated by a steam cylinder, a weight, a
crank, or lever.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Tomlinson Bousfield in the Great Seal Patent Office
on the 24th January 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of 8. Sussex Place, Loughborough Road, Brixton, in
the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of July, in the year of our Lord

page_text: One thousand eight hundred and fifty-five, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
George Tomlinson Bousfield, Her special licence that I, the said George
Tomlinson Bousfield, my executors, administrators, and assigns, or such others
as I, the said George Tomlinson Bousfield, 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 terin 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
"IMPROVEMENTS IN CUTTING WOOD," (a communication,) upon the condition
(amongst others) that I, the said George Tomlinson Bousfield, my executors
or administrators, 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 George Tomlinson Bousfield, do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:―
In mortising chisels heretofore used for cutting mortises in wood, only one
single cutting edge has been employed, whose operation was to cut as much as
the strength of the material of the tool as the character of the wood to be cut
would permit at one single stroke, and then to return and repeat the cut until
the desired quantity of wood had been removed to produce the required
mortise. This single edge has been aided somewhat by using it in combina-
tion with a running augur, working inside of a square cutter, and removing
the wood within its reach by boring, leaving only the square corners to the
chisel, but this tool makes only a square mortise, and is limited in its capacity
to do that by certain limits of size. When used to make a long mortise, it
repeats its operation until the number of squares equals the entire size to be
cut. Running cutters have also been employed to cut mortises, having a
series of tools upon an endless chain sinking gradually into the wood, but
these in practice have been found inferior to reciprocating cutters.
The improvements consist in combining in one single chisel a number of
cutting edges, each one of which cuts only as much as steel edges ought to
cut, and which are so arranged as to follow each other in immediate succes-
sion, gradually widening the mortise until the desired width has been attained.
By this principle a chisel may be made to cut a mortise of any size at a single

page_text: stroke, while at the same time no one of the cutting edges is overstrained, and
the wood is not crushed any more than it would be by a single cut of the
old-fashioned chisel.
In the accompanying Drawings, Figure 1 is a front elevation of one of the
chisels, combined with a guide frame and steam cylinder for working it by
steam; Figure 2 is a side elevation of the same; Figure 3 is a small section
of the chisel. The same letters refer to the same parts in all. A is the chisel,
which is made of a solid plate of steel as thick as the width of the mortise,
and which is gradually tapered from its point to its base, having its opposite
sides similar to each other. The separate cutting edges on these opposite
diverging sides are made by cutting gullets into the plate at an angle of about
45 degrees, with the diverging edges of the tool deep enough to contain and
carry through the mortise the material which the edges above them may cut
from the wood. The diverging line which intervenes between the gullets
gives the best shape for the cutting edges, because it prevents them from
anchoring into the wood, and it enables the operator to sharpen them by the
application of an oil stone to all at once. But the angle of that line with
the gullets may be altered without changing the nature of the operation.
Bis the plank through which the mortise is being made, which rests upon the
table G, and is held in place by the guide D. F, F, are metal jaws, set as
wide apart as the length of the mortise to be cut, so that when the chisel has
been drove through the wood it just touches each of them, thereby preventing
the mortise from splitting out on the lower side. E is a guide screw, whose
point bears against the face of the chisel to prevent its vibration; another one
corresponding with this one is on the opposite side of the chisel. A groove
may be planed into the face of the chisel for these guide screws to run in.
C is a cross head, sliding in ways, and thereby accurately directing the chisel;
I is a steam cylinder, in which a piston travels which drives the chisel, thereby
guiding it both ways through the wood. The manner of operating this chisel
is this: a hole is first bored in the plank in the centre of the intended mortise,
and it is then placed on the table, so that the hole exactly coincides with the
central axis of the chisel, and is there held by any of the known means. The
chisel is then driven down by the steam or by any other power, and as its lower
extremity enters the hole, the first pair of cutting edges square it, and the
chips they make fall through. The next pair cut the mortice as much wider
as their width exceeds that of the first pair, and their chips are carried down
in the gullets below them, and each pair in succession cut their proportion
until all have passed through, when the mortise will be perfect and parallel
throughout. If the tool is stopped short of the entire stroke, the mortise will

page_text: correspond generally in shape with the chisel, but will not have its opposite
sides as smooth as it will when it goes through. The increase of the width of
the chisel between each pair of the cutters on the average should be one-
sixteenth of an inch; but this may be varied to accommodate the depth of
the mortise and the quality of the wood. The length of the chisel also varies
with the length and depth of the mortise to be cut, and the distance between
the cutting edges should not be less than three-eighths of an inch apart; but
that may be varied to suit different cases. It will be apparent that this chisel
may be used as a hand tool, and driven by a mallet as other chisels are, and
that in place of being made solid the opposite diverging sides may be hinged
together at the point, and set at any angle with each other, and that one side
of the chisel may be left plain and vertical, and the cutters all be placed on
the other; and that triangular or any other shaped chisels may be made by
applying to their many sides the series of cutters as described, and that the
angle of the cutting edge with the axis of the chisel may be varied, without
altering the nature of the Invention. Instead of using the ordinary augur for
boring the holes in the centre of the mortise, an auger may be attached to
the point or narrow end of the chisel; and by attaching the chisel to a cylin-
drical slide and revolving the same, the hole can be first bored, and then
the chisel forced through, thereby combining the chisel and augur in one
instrument.
What I claim as the Invention, and desire to secure by Letters Patent,
is, combining in a single chisel a series of cutting edges so arranged as succes-
sively to cut into the wood upon which they operate, and by their combined
action to remove the desired quantity of material at a single operation, sub-
stantially as herein described.
In witness whereof, I, the said George Tomlinson Bousfield, have here-
unto set my hand and seal, this Twenty-third day of January, in the
year of our Lord One thousand eight hundred and fifty-six.
Witness,
W. H. SNELL,
No. 2, New Court,
St. Swithin's Lane.
GEO. T. BOUSFIELD. (L.s.)