Improved Mortise Chisel.
Year: 1899

page_text: Date of Application, 8th Apr., 1899
Complete Specification Left, 13th Nov., 1899-Accepted, 23rd Dec., 1899
Improved Mortise Chisel.
ALEXANDER SUMMERS, 28, Prospero Road, Upper Holloway, N., London,
Wood Machinist, do hereby declare the nature of this invention to be as
follows:-
Two rows of teeth on the back of a mortis chisel, one on either edge of the
groove for drawing the core as made by the chisel thus preventing the accumi-
lation of the core, or residue, as made by ordinary mortis chisels.
Datadh Qth dar of A 1800
ALEXANDER SUMMERS.
COMPLETE SPECIFICATION.
Improved Mortise Chisel.
I, ALEXANDER SUMMERS, of 28, Prospero Road, Upper Holloway, London,
Wood Machinist, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to improvements in core-drawing mortise chisels, and
is designed with the object of providing a chisel of this description which
shall automatically remove the core from the mortise cut in the wood by such
tool, in a ready, convenient and effective manner without the aid of an ex-
traneous core-drawing tool or puncher, as was heretofore necessary.
In order that this my said invention may be the more readily understood and
carried into practical effect, reference is hereby made to the accompanying illus-
trative drawings, wherein:.
Fig. 1 is a side elevational view of my improved mortise chisel
Fig. 2 a rear elevational view of same.
Fig. 3 is a vertical section on line A-B.
Fig. 4 is a transverse section on line C-D, and
Fig. 5 a similar view on line E-F.
Referring to the drawings, wherein like letters of reference indicate corre-
sponding parts throughout the several figures, a represents the blade of the
mortise chisel, which possesses many features in common with the mortise
chisels at present in use, but which has the walls on its rear side, formed by
the lengthwise groove c, serrated to form teeth d.
The said groove c in the rear side of the chisel blade is given a rearward
inclination from the bottom to the top, so that the parallel walls are con-

page_text: siderably deeper horizontally, at their lower ends than at their upper ends as
will be clearly understood from the various sections shewn.
The said rear walls bare serrated for the whole or greater part of their
length, in order to form the saw-like teeth d.
Each of the said teeth d forms only two sides of a triangle, the upper side <
being horizontal and at a right angle with the line of the chisel blade, while
the other side forms an acute angle with the said upper side d¹.
It is important that all of the said teeth d be formed of a corresponding
size.
It will be noticed that by forming the teeth of a uniform size and giving
the groove the inclination before described, only the upper pair of teeth d
extend right back (horizontally) to the bed of the said groove, the other teeth
only extending for a portion of the depth (horizontally) of the rear parallel
walls. b.
Another important feature of my invention consists in forming the blade of
the mortise chisel with its rear edges (comprised by the points of the teeth)
and front edges in an approximately parallel line one with the other, whereby
each of the teeth is caused to perform the maximum amount of work in with-
drawing the core from the mortise, i.e., when the chisel is on the up-stroke
(during the process of removing the core from the mortise) the top pair of
teeth engage with the core and extract a portion thereof, the second pair
coming into operation after the first pair have performed their function, and
so on in the same way all down the several pairs of teeth, all the several pairs
of teeth coming into operation in rotation and taking up their share of the
work left them by the preceding pair.
The walls in my mortise chisel blade extend considerably beyond the front
horizontal edge of the blade , such extended ends of the walls terminating
in acute angled points e as shewn, in order that the chisel may enter the wood
with as little resistance as possible.
In operation, the mortise chisel is fitted, at the shauk a to the mortising
machine in the usual manner, and when such mortise chisel has cut the mor-
tise, the wood in which the latter has been formed is given a reverse travel to
that during the process of cutting the mortise, by this means causing the hard
core which has accumulated in the mortise, to work up against the serrated
edges of the chisel and be withdrawn thereby.
A considerable portion of the core is removed by the action of the mortise
chisel during the operation of cutting the mortise, the remaining portion of
such core being removed subsequently in the foregoing manner.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In core-drawing mortise chisels, the combination of a blade having its
front and rear sides in a parallel plane, one with the other; of an inclined
groove in the rear side of said blade and pointed teeth formed in the parallel
walls produced by such groove, said teeth being all of a uniform size and having
their upper edges at right angles to the line of the blade, substantially as
specified and shewn.
2. In core-drawing mortise chisels, the blade having its rear and front sides
in a parallel plane, one with the other and provided with a rearward groove
extending for the greater part of the length of such blade, said groove being
inclined rearwardly from the bottom to the top thereof; in combination with
the parallel walls on each side of said groove, said walls diminishing in depth
horizontally, toward the upper ends; and the teeth of uniform size formed in
said walls, each of said teeth comprising only the two sides of a triangle, the
upper side being horizontal and the lower side at an acute angle thereto, the
upper pair only of such teeth extending horizontally back to the bed of the

page_text: groove, the others extending only partially through the depth, horizontally, of
said walls; and the bevelled lower ends of said walls extending beyond the
lower horizontal edge of the front of the blade, said ends terminating in points,
all arranged, combined, and operating, substantially as and for the purpose
herein before described and as illustrated by the drawings.
Dated this 13th day of November 1899
HUGHES, SON & Co.,
38, Chancery Lane, London, W.C.,
For the Applicant.