IMPROVEMENTS IN SAWS AND IN HANDLES FOR THE SAME
Year: 1874

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN SAWS AND IN HANDLES FOR THE SAME."-A com-
munication from abroad by Henry Disston, of the City and County
of Philadelphia. State of Pennsylvania, United States of America.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 9th July 1874.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN SAWS AND IN HANDLES FOR THE SAME," a
communication to me from abroad by Henry Disston; of the City and
County of Philadelphia, State of Pennsylvania, United States of America,
follow
.

page_text: adapt to resist end crusts, WHS ITS strengun is at
the same time increased.
· Second. Ordinary cross-cut saws are provided with handles which
must necessarily be grasped at such a point that the line of draught is
above the upper edge of the blade; hence the operator while pulling at
the saw must at the same time have his attention and exertions directed
to the lateral steadying of the blade, while his assistant at the opposite.
end of the saw is powerless as regards the rendering of any aid by
pushing the blade, for as the line of thrust is above the upper edge of
the blade the latter must be buckled whenever such thrust is attempted;
according to this Invention the blade of a cross-cut saw is provided at
each end with a handle similar to but somewhat larger than that of an
ordinary hand saw. These handles are so situate in respect to the blade,
while the handles themselves so restrict the positions of the hands which
grasp them, that the line of both pull and thrust is below the upper
edge of the saw, a position which not only relieves the operators from
much of the duty of attending to the lateral steadying of the blade, and
of preventing the buckling of the same, but enables the operator at one
end of the saw, by pushing the blade, to aid his assistant, who is pulling
at the opposite end. The main exertion of producing the cutting effect
will of course be the duty of the operator who pulls at the blade. He is
materially aided in the performance of this duty by the comparatively
slight thrusting exertion of his assistant at the other end of the saw.
This thrust is permitted not only by the position of the handles but by.
the character of the blade itself, which in the middle is rounded or
bulged at the upper edge; but in lieu of this rounded portion being
continued to the ends of the blades in straight lines as usual, those
portions of the blade are made concave, the curved lines meeting the
rounded or bulged middle of the blade. It has been found that this
form of blade is the best for resisting an end thrust.
Third. In ordinary hand saws the blade is made straight at the broad
end, and the handle is so secured to the blade that the grip is at a
considerable distance from the blade. It will be evident that the nearer
this grip is to the blade the steadier will be the saw in the hands of the
operator, and the more positive and more free from lateral jars will be
the action of the blade; in other words the nearer the grip is to the
blade the more work can the operator perform with comfort to himself.

page_text: For this purpose the blade is cut away at the broad end, and the handle
is slotted to receive the blade, so that a line coinciding with the rear end
of the blade, and drawn at right angles to the cutting edge of the same
will be within the grip. The edge of the opening cut out of the blade is
made to conform to the front edges of the opening in the handle, but it
is not essential that this arrangement should be exactly adhered to,
providing the blade does not project into the opening of the handle.
By thus cutting away the blade, and adapting the handle to the same,
the two can be secured together more firmly than usual by five screws,
instead of three or four as usual, and these screws may be situated at
such points as to insure an increased lateral steadiment to the blade.
The blade also serves to strengthen the narrowest and weakest portion of
the handle. In carrying out this feature of the Invention it has been´
ascertained that it resulted in economy in the consumption of steel, as
in making hand saws the blades are usually cut from a sheet of steel
having one edge of great inequality, and it is usual to cut a considerable
portion of this edge off; whereas by making the end of the saw of the
improved shape much less waste results.
Fourth. The grip of the handle of the saw is of the ordinary shape,
and the front portion of the handle is made rounded, and so as to project
on to and embrace the body of the blade, in which there is formed a
segmental recess, and admits of the suitable arrangement of the bolts.
In this case the handle is attached to the blade by a central bolt situate
at an advanced point in the body of the blade, and at such a distance
from two other bolts as to insure the most effective lateral steadiness and
security of the handle. It will be evident that as the rounded portion of
the improved handle projects further on to the body of the blade than
the ordinary handle, the former must be more firmly secured to the blade
than the latter as far as lateral steadiness is concerned, and this security
is enhanced by the position of the central bolt, which is further from
the butt of the blade than any of the bolts which secure the ordinary
handle; at the same time the central bolt is so far in advance of the
others that the handle must necessarily be more firmly gripped to the
blade than an ordinary handle. In addition to these advantages the
adoption of the improved handle must result in economy in the con-
sumption of wood. Four bolts may be used as in ordinary hand saws of
the larger class for securing the handle to the blade, but three bolts will
in most cases be sufficient.
:...

page_text: The above described mode of constructing the handle and applying it
to the blade permits the carrying out of another feature of this part of
the Invention, namely, the ready adjustability of the blade on the
handle. This is accomplished in the present instance by making slots
in the blade for the admission of the bolts, the slots being arranged so
that after loosening the bolts the blade may be turned for a sufficient
distance on the handle. By this arrangement a workman is enabled to
change the relative positions of the blade and handle to suit his con-
venience and the class of work on which the saw has to be used. The
slots may be in the blade instead of in the handle, but it is preferred to
make them in the latter.
Fifth. In manipulating a compass saw the operator has frequently to
turn the blade laterally to a variety of angles, and sometimes to operate
the saw with the toothed edge uppermost, and the necessity of thus
changing the lateral position of the blade renders a compass saw provided
with the usual handle difficult to manipulate, as the common handle
does not afford the best medium through which the proper leverage can
be exerted when the blade is in many of the positions in which it has to
be held. In many cases also it is desirable for the operator, in order to
handle the saw with the best effect, to use both hands, and the ordinary
handle affords no facility for effecting this with any comfort to the
operator. In order to obviate these defects the handle is arranged in the
following manner:-The eye or opening is of a proper size for receiving
the four fingers of the hand, and the grip portion is of a convenient form
to be grasped; the spurs or projections are dispensed with, and the
handle is precisely similar in conformation on both sides of the central
line, so that it affords every convenience for being manipulated with
comfort to the operator, no matter what position it may occupy. The
handle is provided with a central projection or continuation of such, a
shape as to enable it to be conveniently grasped by the left hand of the
operator whenever a demand for extra exertion requires the use of the
left hand. This continuation also serves to increase the length of the
saw, without requiring a corresponding increase in the length of the
blade, the widest portion of which nearest to the handle is seldom used
in a compass saw. The blades of compass saws are very liable to break
near the point, and hence it is a matter of importance that facilities
should. be afforded for the ready replacement of a broken blade with a
new one. For this purpose the blade is attached to the continuation of

page_text: the handle in the following manner:-This continuation is slotted for
the reception of the blade, which is confined by two screw bolts, one of
which smaller than the other has a plain stem, whilst the other is
reduced in diameter or grooved. The blade is provided at the end which
fits into the handle with a slot terminating in an opening larger in
diameter than the width of such slot, the slot. itself being of a' width
equal to the diameter of the stem of the smaller bolt. The blade is
effectually retained longitudinally in the handle by the larger bolt, the
enlarged portion of the stem of which is contained in the opening at the
termination of the slot. When the blade has to be withdrawn, all that is
nccessary is to so far loosen the nut of the larger bolt as to admit of the
latter being moved upwards until its grooved portion coincides with the
blade, when the latter is at liberty to be removed longitudinally prior to
the insertion of a new blade. Although the slot with its enlargement
and the grooved bolt are preferred, both the latter and the slot may be
uniform throughout, or the bolt may be of one diameter throughout, and
the slot L shaped, which would prevent the accidental withdrawal of
the blade from the handle almost as effectually as the plan first
described.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 6th January 1875.
°
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,•
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of July, in tlie year of
our Lord One thousand eight hundred and seventy-four, in the 38th
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, admini-
strators, and assigns, or such others as I, the said John Henry
Johnson, my executors, administrators, or assigns, should at any time.
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,

page_text: exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN SAWS AND IN HANDLES FOR THE SAME," a communication to me
from abroad by Henry Disston, of the City and County of Philadelphia,
State of Pennsylvania, United States of America, upon the condition.
(amongst others) that. I, the said John Henry Johnson, my executors
or administrators, by an instrument in writing under my hand
and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be
per-
formed, 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 John Henry Johnson, 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, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say:―
The said Invention relates to certain improved modes of constructing
saws and their handles, and fitting the same together, whereby greater
facilities are afforded for manipulating the saw, and for securing, adjusting,
and removing the handle, and an increased cutting effect and other
advantages are obtained.
And in order that the said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings, the
same letters of reference indicating corresponding parts in all the cor-
responding Figures.
The object of the first part of the said Invention is to construct a
hand saw, which shall be lighter, more easy to handle, stronger in pro-
portion to the amount of metal used in the blade, and more free from
tremor in the hands of the operator than ordinary hand saws, and this
object is attained by-making the back of the blade of the form illus-
trated in Figure 1 of the accompanying Drawings.
The object of the second part of the said Invention is to render the
manipulation of a double-handled cross-cut saw more easy for the

page_text: operators than heretofore by arranging the handles in relation to the
blade, and by constructing the back of the latter in the manner illus-
trated in Figure 2 of the Drawing.
The object of the third part of the said Invention is to so construct a
hand saw that it will have a more determinate cutting effect in the
hands of the operator, and be more easy for the latter to manipulate ;|
and so that the handle may be secured more permanently to the blade, á
further object being to secure a longer cutting edge than that of an
ordinary saw in proportion to the material employed. These results are
attained by cutting away the rear of the blade and adapting. the handle
to the same, in the manner illustrated in Figure 3 of the Drawing.
The object of the fourth part of the said Invention is to so construct
the handle of a hand saw and so adapt it to the blade that the two may
be more firmly secured together with a few bolts, while much less wood
is used in making the handle than in those of the usual construction.
A further object of this part of the said Invention is to enable the
operator of the saw to adjust the handle in respect to the blade. These
objects are attained by shaping the handle and butt of the blade and by
securing the said handle to the blade, in the manner illustrated in
Figures 6 and 7 of the Drawing.
The object of the fifth part of the said Invention is to render compass
saws more easy to manipulate than usual, and to afford facilities for the
ready removal of the blades from and their attachment to the handles,
which objects are attained by constructing the handle in. the manner
illustrated in Figure 11 of the Drawing, which is a side view drawn to a
scale of one-half the actual size of the saw, Figures 12 and 13 being
full sized sectional views.
First. The blades of ordinary hand saws are made with a gradual and.
uniform taper, both in width and thickness, from the outer to the inner
end. This conformation has hitherto been considered the best for pre-
venting the lateral yielding of the blade under the end thrust imparted
to it; but notwithstanding this provision the yielding of the blade and
the consequent sudden jars which are so disagreeable to the operator still
take place. In this respect there is much difference between ordinary
saws, even between those which appear to be alike in conformation, and
this difference which is technically termed a difference in the "hang
of a saw is readily detected by an expert carpenter. After repeated

page_text: experiments it has been ascertained that the defect of ordinary saw:
blades consist in the backs being made straight from end to end, as
shown by dotted lines in the Drawing, and in the excessive width of
the blade at and near its middle. Now, according to the said Invention,
the metal is removed at the back to an extent indicated by the space
bounded by the full and dotted lines in the Drawing, and the back is
formed on a very gentle curve from the outer end to about the point b,
from which point the curve becomes more abrupt until it gradually
merges into the round portion a, and from there to the inuer end of the
blade there should be little or no diminution in its width, as it is
essential that the blade should be comparatively-heavy and rigid at and-
near the handle. It has been ascertained that a blade thus formed is.
better adapted to resist end thrusts than ordinary blades, and that it is
more acceptable to all wood working artizans who have used it owing to
its freedom from the jars which so often interfere with the proper
working of ordinary hand saws; in other words the "hang" of the saw
is greatly improved by this mode of constructing the blade. Another
important advantage appertaining to this feature of the Invention is the
increased strength of the blade attributable to the above described.
curved back. When a saw blade with a straight back breaks, the
fracture takes place across the blade in a direction about at right angles
to the cutting edge, owing to the fact that the blade when bent assumes
the form of a plain arch. In bending the blade having the curved back
described however it will assume the form of a skew arch, and hence if
this bending be continued until a fracture occurs that fracture will be on
a diagonal line, as shewn at y. It will be seen therefore that there is
actually more width of blade to fracture in the improved saw than in a.
saw with a straight blade.
Second. Ordinary cross cut saws are provided with handles which
must necessarily be grasped at such a point that the line of draught is
above the upper edge of the blade, hence the operator while pulling at.
the saw must at the same time have his attention and exertions directed
to the lateral steadying of the blade, while his assistant at the opposite
end of the saw is powerless as regards the rendering of any aid by
5 pushing the blade, for as the line of thrust is above the upper edge of
the blade, the latter must be buckled whenever such thrust is attempted.
In the improved cross cut saw illustrated in Figure 2 of the accompany-
ing Drawing, there is fitted at each end of the blade A a handle B
U

page_text: similar to but somewhat larger than that of an ordinary hand saw.
These handles are so situate in respect to the blade, while the handles
themselves so restrict the positions of the hands which grasp them, that
the line x, x, of both pull and thrust will necessarily be below the upper
edge of the saw, a position which not only relieves the operators from
much of the duty of attending to the lateral steadying of the blade and
of preventing the buckling of the same, but enables the operator at one
end of the saw, by pushing the blade, to aid his assistant who is pulling
at the opposite end. The main exertion of producing the cutting effect
will of course be the duty of the operator who pulls at the blade. He is
materially aided in the performance of this duty by the comparatively
slight thrusting exertion of his assistant at the other end of the saw.
This thrust is permitted not only by the position of the handles, but by
the character of the blade itself, which in the middle is rounded at the
upper edge, as shewn at 6; but in lieu of this rounded portion being
continued from f,f, to the ends of the blades in straight lines as usual,
those portions of the blade are made concave, the curved lines
meeting the rounded middle of the blade, as shown. It has been found
that this form of blade is the best for resisting an end thrust.
Third. In ordinary hand saws, the blade is made straight at the broad.
cud, as shown in Figure 4, and the handle is so secured to the blade
that its portion a, or as it is commonly termed the grip, is at a consider-
able distance from the blade. It will be evident that the nearer this
grip is to the blade the steadier will be the saw in the hands of the
operator, and the more positive and more free from lateral jars will be
the action of the blade; in other words, the nearer the grip is to the
blade the more work can the operator perform with comfort to himself.
For these reasons the blade is cut away at the broad end in the manner
shown in Figure 3, and the handle is slotted to receive the blade, so
that a line x, x, coinciding with the rear end of the blade and drawn at
right angles to the cutting edge of the same will be within the grip a.
The edge of the opening m cut out of the blade is made to conform to
the front edge of the opening in the handle, but it is not essential that
this arrangement should be exactly adhered to, providing the blade does
not project into the opening of the handle. By thus cutting away the..
blade and adapting the handle to the same, the two may be secured
together more firmly than usual by five screws instead of by three or
four as in the ordinary manner, and these screws may be situate at such

page_text: points as to insure an increased lateral steadying of the blade. The
blade also serves to strengthen the narrowest and weakest portion to of
the handle. In carrying out this feature of the Invention it has been
ascertained that it resulted in economy in the consumption of steel in a
manner which will be best understood by reference to the diagram
Figure 5. In making hand saws, the blades are cut from a sheet of steel
having one edge of great inequality, and it is usual to cut a considerable
portion of this edge off. Thus in Figure 5, A represents a portion of
one of the crude plates which must be severed on about the line y, y, in
making ordinary blades with straight broad ends, but a considerable
portion of this scrap may be embodied in the improved blades, as
shewn in Figure 5, and a longer cutting edge will thus be insured.
"
Fourth. The grip a of the handle of, the saw, illustrated in Figures 6
and 7, is of the ordinary shape which custom and convenience demands,
but the front portion of the handle is made rounding, and so as to
project on to and embrace the body of the blade and permit the arrange-
ment of the bolts b, c, and d, in the manner shown, the central bolt
being at an advanced point in the body of the blade, and at such a
distance from the bolts and d as to insure the most effective lateral
steadiness and security of the handle. The advantage of this mode of
constructing the handle will be best understood on reference to the
diagrams, Figures 8 and 9, the patched portion of the former represent-
ing the extent of the grip of an ordinary handle on an ordinary blade,
and the patched portion of Figure 9 representing the grip of the
improved handle on the blade, from the butt of which is cut the
segmental piece defined by the line a. It will be evident that as the
rounded portion of the improved handle projects further on to the body
of the blade than the ordinary handle, the former is necessarily moro
firmly secured to the blade than the latter, as far as lateral steadiness is
concerned, and this security is enhanced by the position of the central
bolt c, which is situate further from the butt of the blade than any of
the bolts which secure the ordinary handle; at the same time the central
bolt is so far in advance of the others that the handle must necessarily
be more firmly gripped to the blade than an ordinary handle. In
addition to these advantages the adoption of the improved handle
necessarily results in economy in the consumption of wood, as will be
readily understood on reference to Figure -10, which indicates by dotted
and full lines, the relative sizes of the ordinary and the improved
•

page_text: с
handles. If desired, four bolts may be used as in ordinary hand saws of
the larger class for securing the handle to the blade, but three bolts will
in most cases be sufficient.
The above described mode of constructing the handle and applying it
to the blade admits of the carrying out of another feature of this part
of the Invention, namely, the ready adjustability of the blade on the
handle. This is accomplished in the present instance by making slots e
in the blade for the admission of the bolts, the slots being arranged.as
shown, so that after loosening the bolts the blade may be turned on the
handle from the position shown in full lines to that indicated by dotted
lines. By this arrangement a workman is enabled to change the relative
positions of the blade and handle to suit his convenience and the class
of work on which the saw has to be used. The slots may be in the blade
instead of in the handle, but it is preferred to make them in the latter.
Fifth. In manipulating a compass saw the operator has frequently to
turn the blade laterally to a variety of angles, and sometimes to operate
the saw with the toothed edge uppermost; and the necessity for thus
changing the lateral position of the blade renders a compass saw
provided with the usual handle difficult to manipulate, as the common
handle. does not afford the best medium through which the proper
leverage may be exerted when the blade is in many of the positions in
which it has to be held. In many cases also it is desirable for the
operator, in order to handle the saw with the best effect, to use both
hands, and the ordinary handle affords no facilities for effecting this with
any comfort to the operator. In order to obviate these defects the
handle A is made in the manner shown in Figure 11; the eye or
opening a being of a proper size for receiving the four fingers of the
hand, and the portion 6 of a convenient form to be grasped; the handle
is precisely alike in conformation on both sides of the central line x, so
that it affords every convenience for being manipulated with comfort to
the operator, whatever position it may occupy. The handle is provided
with a central projection or continuation d of a shape, substantially as
shown in Figure 11, so as to enable it to be conveniently grasped by the
left hand of the operator whenever a demand for extra exertion requires
the use of the left hand. This continuation also serves to increase the
length of the saw without requiring a corresponding increase in the
length of the blade, the widest portion of which nearest to the handle is
seldom used in a compass saw. The blades of compass saws are very

page_text: liable to break near the point, and hence it is a matter of importance
that facilities should be afforded for the ready replacement of a broken
blade with a new one. For this purpose the blade is attached to the
continuation d of the handle in the manner illustrated in the enlarged
secțional views, Figures 12 and 13. This continuation is slit for the
blade which is confined by two bolts e and e', as shewn clearly in
Figure 13, the latter bolt having a plain stem and the former being
reduced in diameter or grooved at f, as seen in the detached view,
Figure 14. The blade B is provided at the end which fits into the
handle with a slot m terminating in an opening n larger in diameter
than the width of the slot, as shewn in Figure 12, the slot itself being of
a width equal to the diameter of the stem of the bolt e¹. The blade is
thus effectually retained longitudinally in the handle by means of the
bolt
the enlarged portion of the stem of which is contained in the
opening n at the termination of the slot m. When the blade has to be
moved all that is necessary is to so far loosen the nut of the bolt e as to
admit of the latter being pushed in the direction of the arrow until its
grooved portion f coincides with the blade, when the latter is at liberty
to be removed longitudinally prior to the insertion of a new blade in a
manner which requires no explanation. Although the slot m with its
enlargement and the grooved bolt e are preferred both the latter and
the slot may be uniform throughout; or the bolt may be of one diameter
throughout and the slot made L shaped, which would prevent the
accidental withdrawal of the blade from the handle almost as effectually
as the plan first described.
e,
Having now described and particularly ascertained the nature of
the said Invention and the manner in which the same is or may be used
or carried into effect, I would observe in conclusion that what I
consider to be novel and original and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent is,―
First. A hand saw blade with a back edge made of the peculiar curved
form that is rounded or convex near the butt, and concave throughout
the remaining portion of its length, substantially as herein-before
described and illustrated by Figure 1 of the accompanying Drawings.
Second. A cross-cut saw, having a blade provided at each end with
a handle similar in shape to that of an ordinary hand saw, the position
of the portions of the said handles to be grasped by the hands being so
arranged that, the line of pull and thrust will be below the upper edge

page_text: of the blade, substantially as herein-before described and illustrated by
Figure 2 of the accompanying Drawings.
Third. The cross-cut saw blade A having its upper edge made of a
rounded form in the middle at b, and of a concave form at e, sub-
stantially as and for the purpose herein-before described, and as
illustrated by Figure 2 of the accompanying Drawings.
:.
.
Fourth. A hand saw in which the rear of the blade is cut away and
adapted to the handle, substantially in the manner and for the purpose
herein-before described, and illustrated by Figures 3 and 5 of the
accompanying Drawings.
Fifth. The combination of the blade having a segmental recess x at
the butt, with the handle rounded in front, where it embraces the blade,
and with bolts arranged so that the central bolt or bolts shall be in an
advanced position on the blade, substantially as herein-before described
and illustrated by Figures 6 and 7 of the accompanying Drawings..
Sixth. The blade with its segmental recess x, the rounded portion of
the handle, and three or more bolts adapted to slots arranged in the
handle or blade, substantially as and for the purpose herein-before
described, and as illustrated by Figures 6 and 7 of the accompanying
Drawings.
Seventh. A compass saw handle, in which are combined an eye or
opening a for admitting four fingers, the portion 6 to be grasped by one
hand, and a continuation d of appropriate shape to be seized by the other
hand, all substantially as herein-before described and illustrated by the
accompanying Drawings.
Eighth. The combination with the compass saw handle of bolts è
and e¹ adapted to a slot m in the blade, substantially as herein-before
described and illustrated by the accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, the Thirty-first day a
of December, One thousand eight hundred and seventy-four.
I HENRY JOHNSON