IMPROVEMENTS IN RASPS AND FILES
Year: 1870

page_text: LETTERS PATENT to William Robert Lake, of the "International
Patent Office," Southampton Buildings, London, Consulting
Engineer, for the Invention of "IMPROVEMENTS IN RASPS AND FILES."
-A communication from abroad by Ira Franklin Thompson, of
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition, on
the 23rd September 1870.
I, WILLIAM ROBERT LAKE, of the " "International Patent Office,"
Southampton Buildings, London, Consulting Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN RASPS And
FILES," a communication, to be as follows:- -
This Invention relates to a novel construction of rasps and some
species of files, whereby the cutting faces of such instruments may be

page_text: made much more lasting and effective than at present, and when worn
out may be renewed at small cost and with very little labour; and the
said Invention consists, primarily, in the employment of a permanent
shank or base covered by toothed metallic plates, which can be readily
attached to and removed therefrom in a manner and for the purpose
herein-after explained. I take a long narrow and thin bar of metal of
about the size and shape of a rasp as now generally used, such bar con-
stituting the base or shank of the instrument, and which in practice I
form of iron. The shank has a tapering prong for insertion within a
proper handle.
The moveable cutting plates are composed of thin flat
ribbons of steel of about equal length with the bar before mentioned.
The teeth of these plates are composed of alternating rows of thin concave
projections, struck up from the inside of the ribbon-by a suitable die or
punch in such a manner as to present a series of sharp curved teeth,
the concavities of the teeth forming receptacles for the matter thus cut
away, and aiding to a great extent the free and effective working of
the implement. The ribbons of steel may be applied to the shank by
screws with countersunk heads, or they may be soldered directly to such
shank; or I may affix to or form upon each end of each cutting plate,
and upon opposite sides thereof, a shallow ledge or catch, while upon the
outer end of each side of the shank I cut two shallow depressions or
notches for the reception of one of the catches of each cutting plate
which lock into them. Two jaws are provided with semi-cylindrical
shanks, upon which a male screw or portion of the threads of a screw
is cut, each of the said jaws being provided with a hook or catch similar
to those of the plate, such catches overlapping and taking into the
catches of the plates before described. The handle of the instrument
is made substantially in the usual form, except that it is provided
internally with a tubular sleeve upon which is cut a female screw for
enclosing the shanks of the jaws. Alternate rows of teeth may present
their cutting faces in opposite directions to the adjacent rows, and the
cutting faces of such teeth may be placed obliquely to the largest axis
of the plate. Under the alternate disposition of the teeth last men-
tioned, when one series of the same become worn out the plates may be
reversed, end for end, which will double the capacity of the instrument.
Or I may produce a duplicate series of teeth struck up from the opposite
side of the plate, the cutting faces of both series of teeth being produced
by the same puncture of the metal, and being in alignment with each

page_text: other, but as a matter of necessity presenting their cutting edges in
opposite directions. When the series of teeth upon one side of the
plate become worn such plate is to be removed from the shank and so
reversed as to present the opposite series of teeth outermost. The two
surfaces of the shank should be provided with a series of creases or
cuts to afford a free passage for the discharge or escape of the filings,
and for horse-shoe and woodwork rasps the shank should be provided
with a series of cavities and projections corresponding in size and form
to the teeth on the inside of the plate to prevent clogging. For certain
species of rasps the steel plates may be very thin, in which case the
teeth produced therefrom will preserve a cutting edge for a great length
of time. Should it become necessary to employ a thicker plate of steel in
order to obtain sufficient strength at the base or support of the teeth,
the outer extremities of these teeth for some distance should be reduced
considerably in thickness, in order to acquire and maintain a cutting
edge. The shank may be of curvilinear form in longitudinal section,
being thicker at an intermediate point than at either of the ends, this
form being better adapted for securing the plates upon the surfaces of
the shank than where the shank is of rectangular form. The surfaces
of the shank upon which the plates are to be applied should be covered
with solder or soft metal, in order that an elastic or yielding bed may be
afforded for the teeth of the plates to rest on. I may use two toothed
plates secured to their shank or base by means of a wedge-shaped pin
or key. The shank is here provided with two circular projections, over
which one end of the toothed cutting plate is caught, the other end of
the plate hooking over two similar projections, the wedge-shaped pin
or key is driven in between the end of the shank and the block and
the plate is tightened as required, the key is provided with a rib or
tenon on one side to fit into a channel or groove in the end of the
shank, and the other side of the key is rounded so as to fit into a groove
of corresponding form in the inside of the block so that the key may
be kept in place. In making these plates after they are provided with
teeth on both sides, I polish their ends and then punch the holes which
are to receive the projections, after which I tin the ends to make them
adhere when turned over and subjected to heat. But if desired separate
pieces may be soldered to the ends
applied to either end of the shank,
made as above described may be
or cylinder, which may be hung in bearings and revolved by hand
of the plates and the key may be
One or more toothed cutting plates
applied to the surface of a drum

page_text: or other power, thus forming a revolving rasp which may be employed
for dressing and finishing stone or for any other purpose for which it
may be found applicable.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 15th March 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International Patent Office," Southampton
Buildings, London, Consulting Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of September, in
the year of our Lord One thousand eight hundred and seventy, in the
thirty-fourth year of Her reign, did, for Herself, Her heirs and successors
give and grant unto me, the said William Robert Lake, Her special
licence that I, the said William Robert Lake, my executors, adminis-
trators, and assigns, or such others as I, the said William Robert
Lake, 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 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
"IMPROVEMENTS IN RASPS AND FILES," a communication to me from abroad
by Ira Franklin Thompson, of Boston, Massachusetts, United States of
America, upon the condition (amongst others) that I, the said William
Robert Lake, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 William Robert Lake, 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
Drawing forming a part of this Specification.

page_text: This Invention relates to a novel construction of rasps and some
species of files, whereby the cutting faces of such instruments may be
made much more lasting and effective than at present, and when worn
out may be renewed at small cost and with very little labour; and the'
said Invention consists, primarily, in the employment of a permanent
shank or base covered by toothed metallio plates which can be readily
attached to the said shank and removed. therefrom in a manner and for
the nurnose herein after explained:
9
Figure 1 is a perspective view of a rasp in which my Invention in one
of its forms is embodied; Figure 2 is a longitudinal section of the same;
Figures 3, 4, 5, 6, 7, and 8 represent modifications of my Invention..
A denotes a long, narrow, and thin bar of metal of about the size and
shape of a rasp as now generally used, such bar constituting the base
or shank of the instrument, and which in practice I form of iron as
answering the purpose equally as well as steel and being of much less,
cost. The shank A has a taper prong B for insertion within a proper
handle. One of the moveable cutting plates which I adopt in carrying
out my Invention is shown at C, as composed of a thin flat ribbon of
steel of about equal length with the bar A before mentioned, shown in
Figure 1. The teeth of these plates shown at a, a, are composed of
alternating rows of thin concavous projections struck up from the inside
of the ribbon by a suitable die or punch, in such a manner as to present
a series of sharp curved teeth of the best practical form for rasping or
reducing a horse's hoof or other substance to which the instrument may
be applied, the concavities of the teeth forming receptacles for the matter
thus cut away and aiding to a great extent the free and effective working
of the implement. The above mentioned ribbons of steel may be applied
to the shank A of the rasp in various ways, for instance, they may
be secured thereto by screws with countersunk heads, or they may be
soldered directly to such shank, or they may be held in place in any
other suitable manner.
One method of applying the cutting plates to the shank is shown in
Figure 2 of the accompanying Drawing. I affix to or form upon cach
end of each cutting plate and upon opposite sides thereof a shallow ledge
or catch 6 or c, while upon the outer end of each side of the shank

page_text: A I cut two shallow depressions or notches d, d, for reception of the
catches of each cutting plate which lock into them. D, D', represent
two jaws provided with semi-cylindrical shanks e, e¹, upon which a male
screw or portion of the threads of a screw is cut, each of the said jaws
being provided with a hook or catch f similar to those of the plate C,
such catches f overlapping and taking into the catches c, c, of the
plates C, C, before described. The handle of the instrument is shown
at E, as made substantially in the usual form of such articles, except
that it is provided with a tubular sleeve g, upon which is cut a female
screw for enclosing and encompassing the shanks e, e¹, of the
jaws D, D¹. It is evident that upon screwing the handle E upon the
semi-shanks e, e¹, until the ferrule i of such handle comes in contact
with the shoulders produced at the junction of the shank A and its
prong B, any further advance of the handle will exert a powerful
draught or tension upon the cutting plates C, C, sufficient to maintain
them securely in position under all conditions of service. This mode
of securing the cutting plates to the shank while being durable and
effective allows them to be readily detached therefrom if occasion
requires. Although in the present instance I have represented a given
form and disposition of the teeth a, a, it is evident that various modifica-
tions may be made of the same without affecting the characteristic
feature of my Invention, which as before stated consists in the adaptation
of moveable cutting plates applied longitudinally to a permanent base
or shank. Although in the annexed Drawing the teeth a, a, are so
produced and arranged as to present their cutting edges in one direction
and longitudinally with and at right angles to the longest plane of the
plate, I have contemplated several modifications in the production and
disposition of such teeth. For instance, alternate rows of teeth may
present their cutting faces in opposite directions to the adjacent rows
and the cutting faces of such teeth may be placed obliquely to the
Under the alternate disposition of the teeth
last mentioned, when one series of the same becomes worn out the plates
may be reversed end for end, which will double the capacity of the
longest axis of the plate.

page_text: both series of teeth being produced by the same puncture of the metal,
and being in alignment with each other, but as a matter of necessity
presenting their cutting edges in opposite directions. When the series of
teeth upon one side of the plate becomes worn such plate is to be removed
from the shank A and so reversed as to present the opposite series of
teeth outermost.
Under this last-mentioned formation and classification of teeth the
two surfaces of the shank A should be provided with a series of creases
or cuts (as seen on the upper side of Figure 6) to afford a free passage
for the discharge or escape of the filings, and for horse-shoe and wood-
work rasps the shank should be provided with a series of cavities and
projections corresponding in size and form to the teeth on the inside of
the plate to prevent clogging. For certain species of rasps the steel
plates C, C, may be very thin, in which case the teeth produced there-
from will preserve a cutting edge for a great length of time. Should it
become necessary to employ a thicker plate of steel in order to obtain
sufficient strength at the base or support of the teeth the outer extre-
mities of these teeth for some distance should be reduced considerably
in thickness in order to acquire and maintain a cutting edge. This
reduction of the teeth may be accomplished by the same agency and
at the same time as the striking up of the teeth.
I would remark that the principle of my Invention does not preclude
the making of taper, convex, round, or curved rasps and files, as
these may be produced with equally good results if not with equal economy
as compared with flat rasps.
In the perspective view, Figure 4, the shank is of curvilinear form in
longitudinal section, being thicker at a point 10 than at either of the
ends 11 or 12, this form being better adapted for securing the plates more
snugly upon the surfaces of the shank than where the shank is of rect-
angular form in longitudinal section, and the vibration incident to the
latter is thereby avoided. The surfaces of the shank upon which the
plates are to be applied should be covered with solder or soft metal, in
order that an elastic or yielding bed may be afforded for the teeth of the
plates to rest on.
Figure 5 is a longitudinal section representing two toothed plates
secured to their shank or base by means of a wedge-shaped pin or key N.
The shank is provided with two circular projections o, o, Figure 6, over

page_text: which one end of the toothed cutting plate is caught, the other end of
the plate hooking over two similar projections p, p, on a small block M
of the form shown, the wedge-shaped pin or key N being driven in
between the end 12 of the shank and the block M, by which means the
plate is tightened as required, the key being provided with a rib, or
tenon q on one side to fit into a channel or groove r in the end 12 of
the shank, and the other side 13 of the key being rounded so as to fit
into a groove 14 of corresponding form in the inside of the block, so that
the key may be kept in place and not work loose and press outward
against the surfaces of the plates.
In making my said plates after they are provided with teeth on both
sides I polish their ends and then punch the holes which are to receive
the projections o, o, p, p, after which I tin the ends to make them
adhere when turned over and subjected to heat, which gives them
additional strength as a precaution to prevent the holes in the plates
from tearing out when stretched, but if desired separate pieces may be
soldered to the ends of the plates and the key N may be applied to either
end of the shank, but I prefer the construction shown in Figures 4, 5, 6,
and 7. I also prefer the use of the key for stretching the plates upon
their shank or base, as it is more readily operated and the plates can be
put in position and removed more expeditiously than where the device
shown in Figure 2 is employed.
One or more toothed cutting plates made as above described may be
applied to the surface of a drum or cylinder (Figure 8), which may be
hung in bearings and revolved by hand or power, thus forming a revolving
rasp which may be employed for dressing and finishing stone or for any
other purpose for which it may be found applicable.
One advantage resulting from the adoption of the Invention above.
described will be found in the fact that I am enabled to produce the
teeth of rasps not only more perfect but much more durable than
heretofore.
In addition to this advantage another source of economy consists in
the low cost of the cutting plates as compared with a rasp of ordinary
manufacture, as it is evident that a pair of these plates will be equal to
and in fact much more effective and durable than an ordinary rasp which
is composed entirely of steel.

page_text: As these cutting plates are produced by machinery in exact duplication
and in great numbers at very small cost, a person possessing one shank
or base may be enabled to renew its effectiveness by reversing, turning
over, or changing its moveable plates, the saving to him in the expense
being not only the difference between the cost of an entire steel rasp as
compared with that of a pair of cutting plates, as before described, but
between the efficiency and durability of the ordinary teeth as compared
with those shown in my Invention.
Having thus fully described the said Invention as communicated to
me by my foreign correspondent, I claim,-
First. A rasp or file composed of a permanent shank or base and
one or more removeable cutting plates provided with teeth upon one or
both sides applied to the same, substantially as and for the purpose before
explained.
Second. The method of stretching and confining the toothed cutting
plates upon their shank or base by means of a key N and block M,
substantially as described.
Third. The method of stretching and confining the toothed cutting
plates upon their shank or base by means of the catches b, c, d, f, and
sectional screw's e, e¹, the latter being actuated by the handle of the file,
substantially as described.
Fourth. In a rasp or file made as before described producing the teeth
of the moveable cutting plates thereof. upon both sides of the same,
whereby the wearing qualities of the instrument are greatly increased,
substantially as set forth.
Fifth. Indenting the faces of the shank of the instrument for the
reception of the teeth of the moveable cutting plates, substantially as
herein-before described.
Sixth. Producing the teeth of rasps by punching them up from thin
plates of metal, substantially as before explained.
Seventh. A shank or base of a curvilinear form in longitudinal section,
substantially as and for the purpose described.
Eighth. A shank or base having its surfaces covered with solder or
soft metal, as and for the purpose set forth.

page_text: Ninth. A drum or cylinder covered with one or more toothed cutting
lates, as and for the purpose described.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this Fifteenth day of March, in the
year of our Lord One thousand eight hundred and seventy-
one.
Witness,
E. C. JACKSON.
WILLIAM ROBERT LAKE. (L.S.)