IMPROVEMENTS IN GRINDING OR SHARPENING CUTTING TOOLS, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN
Year: 1877

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
GRINDING OR SHARPENING CUTTING TOOLS, AND IN THE MACHINERY OR
APPARATUS EMPLOYED THEREIN," A communication from abroad by Frédéric
Guillaume Kreutzberger, of Paris, in the Republic of France, Engineer.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 24th October 1877.
"
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. IMPROVEMENTS IN GRINDING OR SHARPENING CUTTING TOOLS, AND
IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN." A communication from
abroad by Frederic Guillaume Kreutzberger, of Paris, in the Republic of France,
Engineer.
This Invention relates chiefly to an improved mode of grinding or sharpening
rotatory dentated cutters, such, for example, as boring bits, rimers, and the like,
and to improved apparatus for carrying the same into effect; and it has for its object
chiefly providing facilities for the performing that operation on cutters of varying
shapes with the use of one and the same apparatus.
One important feature of the apparatus consists in the use of what the Inventor
designates a metal hand, which enables the cutters to be presented at any angle by
means of a combination of moveable axes, each having an independent rotary
motion. Conical cutters may thus be applied to the stone according to the angle of
the cones; cutters with oblique teeth, according to the obliquity of the teeth;
cutters with helical teeth, according to the pitch of the helix; and cutters with
curved teeth, according to the mean centre of any geometrical or irregular figure.
Another feature of the apparatus consists in mounting the grindstone in a holder
formed of a jointed and carefully balanced oscillating frame.
The machine employed in carrying out this Invention is composed of a table

page_text: I
having fixed thereon two supports or brackets carrying an axis on which is mounted
one end of an oscillating or adjustable frame, the opposite extremity of which is
provided with a steel sleeve, in which the spindle carrying the grindstone works.
This spindle is provided at one extremity with a pulley which receives its motion
from another pulley mounted upon a transverse shaft driven by any suitable prime
mover.
The frame, which is balanced in its position parallel to its axis when moved for
adjustment or otherwise, slides, in describing an arc of a circle, against a support
fixed upon the table, and when brought into the most suitable position for effecting
the grinding or sharpening which it is desired to perferm, is secured by a bolt
passing through the support and the side of the frame, and tightened by a nut.
To the upper part of the support is jointed a lever provided with a counterweight
and connected to the frame by a rod so as to enable a reciprocating up-and-down
motion to be imparted to the latter, and to bring it to any required position in
which it may be fixed to the support by means of the bolt and nut. Or after
loosening the nut, the frame may be moved as required in order to cause the grind-
stone to follow the shape of the cutters to be sharpened.
A compound slido rest is provided for the facility of adjusting the position of the
cutter, and of moving it longitudinally during the operation of grinding or
sharpening. That portion of the slide rest which gives the longitudinal motion is
provided with a bracket or support capable of rotating on a vertical axis and carrying
at its upper part a split socket, to which is pivotted a split sleeve enclosing a spindle
fitted at one end with a crank handle. The split sleeve is free to turn in the socket
on the support and may be placed at any required angle, and the spindle is capable
of rotating in the split sleeve, the two being retained in position by a set screw.
The other extremity of the spindle is provided with a split head through which is
passed a rod having a lever arm which carries the cutters to be sharpened. This
lever arm is capable of being raised or lowered at will, and of sliding backwards
or forwards in the split head on the spindle in which it is retained by a screw.
The cutter which is placed on a small mandril fixed by screws to the lever arm
is capable of turning freely upon a smooth part provided at the extremity of the
mandril. The lever arm also carries a small pawl which is capable of assuming
different positions and of engaging in the teeth of the cutter so as to divide the
teeth properly. The cutter may thus be brought with facility under the action of
the grindstone, whatever may be its dimensions or shape, or the inclination of its
teeth, and the generating line of the tooth may always be brought parallel to the
direction of the motion of the slide which effects the displacement of the cutter
during the operation of sharpening.
In order to sharpen cutters having a non-perforated stem, and which consequently
cannot be mounted on the mandril or cutter holder herein-before described, it is
proposed to employ a holder constructed in the following manner-It is composed
of three parts, one of which (provided with a V shaped notch) is jointed to a second
part and secured thereto by a screw, whilst the third part consists of a spring fixed
upon the second part and placed with its extremity, which is slightly concave,
immediately above the notch in the first part.
A sinall eccentric centre is provided which supports the centre of the cutter to be
sharpened whilst the stem of the latter lies in the V notch in the holder, where it
is adjusted on its true centre. This arrangement is applicable to the sharpening of
rimers and all tools which are not perforated at the centre.
The sharpening or grinding action takes place in a direction at right angles to
the cutting edge, that is to say, every part of the grinding disc or stone acts succes-
sively on the edge of the tooth, whilst the cutter moves longitudinally so as to
present every portion of the tooth in succession to the action of the disc or stone.
In the case of conical cutters with straight teeth during the sharpening process,
the generating line of the cone is placed horizontally, and the grinding disc acts in
the same direction and in the same manner as when operating on a cylindrical
cutter.

page_text: In order to sharpen a cutter with radiating teeth at right angles to its axis, the
cutter is placed with its axis vertical and the teeth upwards so as to partake of the
motion of the carrier. The sharpening operation is then effected in the same
manner as with cylindrical cutters.
The mode of sharpening a conical cutter with inclined teeth is similar to that
employed for the conical cutter with teeth in the same plane as the axis, but the
cutter holder is suitably inclined so as to present the edges of the teeth at right
angles to the motion of the grindstone or disc.
In operating upon dentated rotating cutters of a curved section, the cutter is first
placed on the holder on the lever arm, and the screw which holds the spindle in the
split sleeve is then loosened, and by means of the crank handle rotary motion is
imparted to the spindle and consequently to the cutter.
By adjusting the cutter in such a manner as to cause the mean centre of the
curves of the teeth to correspond with the centre of rotation of the spindle which
carries the cutter, and then moving the oscillating frame carrying the grinding disc
by hand by means of the lever provided for that purpose, and, turning the crank
handle, the cutter will be sharpened according to its shape by following the curves
so as not to injure the profile of the cutter.
In the case of a cylindrical cutter with helical teeth the pawl, in lieu of being
placed upon the lever arm as in the case of a cutter with teeth parallel to its axis,
is fixed to the stationary support by means of a cylindrical rod placed in a hole
provided for its reception.
It should be observed that on changing the position of the cutter by means of the
slide which gives the longitudinal motion, the tooth slides over a stationary paw]
suitably located, which will impart to the cutter a rotatory motion corresponding to
the inclination of the teeth.

page_text: 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 20th
April 1878.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields; in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN GRINDING OR SHARPENING CUTTING TOOLS, AND
IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN." A communication from
abroad by Frederic Guillaume Kreutzberger, of Paris, in the Republic of France,
Engineer.
The gradual extension of the use of rotatory, dentated, or serrated cutters in
mechanical construction has rendered it necessary to provide special machines for
grinding or sharpening the same on scientific principles.
Heretofore these machines have been constructed with a view to facilitate the
operation of grinding or sharpening, but they are incapable of accommodating
themselves to all the combinations of shapes and outlines of the teeth of which
this class of tools offers such numerous and varied examples. Attempts have how-
ever been made to introduce mechanical appliances for effecting the combined
objects, but the principle of construction having been defective and the accessory
apparatus wanting in completeness, the results obtained have been unsatisfactory
which has prevented the general adoption of such appliances.
Now the said Invention has for its object rendering machines for grinding or
sharpening rotatory, dentatory, or serrated cutters applicable to all cases which can
occur in practice, and this object is attained partly by improvements in the mode
of grinding or sharpening and by the combination with the machine of an apparatus
which the Inventor designates a metal hand, which enables the cutters to be pre-
sented at any angle by means of a system of moveable axes, each having an
independent rotary motion, so as to enable conical cutters to be applied to the
stone, according to the angle of the cones; cutters with oblique teeth, according to
the obliquity of the teeth; cutters with helical teeth, according to the pitch of the
helix; and cutters with curved teeth, according to the mean centre of the particular
geometrical or irregular figure.
A further feature of the said Invention consists in mounting the grindstone
in a holder composed of a jointed and carefully balanced adjustable or oscillating
frame.
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 Figures.
Figure of the accompanying Drawings represents a front elevation of the
improved machine; Figure 2 is a side elevation, and Figure 3 a plan, both corre-
sponding to Figure 1.
Figures 4 and 5 are detached views illustrating a modification of the cutter
holder.
Figures 6 to 13 shew the respective positions of the cutters and grindstones
during the operation of grinding or sharpening in the principal cases which occur in
practice.
Figure 14 is a detail illustrating a modification of one of the parts.
A is a table supporting the whole of the apparatus, and which may be placed
indifferently either on a cast-iron stand or on a wooden bench. Upon the table
there are fixed two supports or brackets a, carrying axes 1, 1, on which is mounted
one end of an oscillating or adjustable frame B, the opposite extremity of which is
provided with a steel sleeve b, in which the spindle 2 carrying the grindstone
works. Fast on one end of this spindle is a pulley c which receives its motion from
a pulley C mounted upon a transverse shaft D, the latter being provided with fast
and loose pulleys F, E', driven by any suitable prime mover, whilst the other

page_text: extremity of such spindle carries the said grindstone d which is capable of being
brought into contact with a dentated cutter R.
The frame B, when moved for adjustment or otherwise, describes an arc of a
circle, and in so doing slides against a support F fixed upon the table, and when
brought into the most favorable position for effecting the grinding or sharpening
which it is desired to perform, may be secured by a bolt g passing through the
support and the side of the frame, and tightened by a fly nut gl.
To the upper part of the support F is jointed a lever provided with a counter-
weight f, and which is connected to the frame B by a connecting rod e so as to
enable a reciprocating up-and-down motion to be imparted to the latter when
necessary, and to bring it into any required position, in which it may be fixed to
the support F by means of the bolt y and fly nut g¹.
When it is required that the frame B should be moved in order to cause the
grindstone to follow the shape of the cutters to be ground or sharpened, the nut g¹
is to be loosened, as will be well understood.
At one corner of the table on the same side as the grindstone d there is provided
a dovetailed projection H, having fitted thereon a slide rest or carrier I to which
a longitudinal motion is imparted by means of a crank handle h, in order to enable
the cutter holder, which is carried in a manner herein-after explained, to be moved
in a direction transverse to its axis into a proper position for the grinding or
sharpening operation.
In a dovetailed groove in the carrier I is fitted a slide or carrier J which is
capable of receiving motion transversely to the carrier I by means of a crank
handle j, and serves to move the cutter longitudinally during the operation of
grinding or sharpening.
1
The carrier J carries a bracket or support L.capable of rotating on a vertical
axis 3, and provided with a split sleeve or socket ; the latter embraces a pin k
carrying another split sleeve or socket m which encloses a spindle fitted with a
crank handle M. The pin carrying the split sleeve m is free to turn in the split
sleeve on the support L, and may be placed at any required angle, being retained
in position by means of a set screw ; in like manner the spindle n, which is
capable of rotating in the split sleeve m, is retained in position by a set screw m'.
The other extremity of the spindle n is provided with a split head n', through
which is passed a rod N having a lever arm N' which carries the cutter R to be
sharpened. This lever arm is capable of being raised or lowered at will, and of
being traversed backwards or forwards by moving the rod N in the split head n',
in which it is retained in position by a set screw n".
The cutter R, which is placed on a small mandril t, fixed by screwing and by two
nuts t, t, to the lever arm N', is capable of turning freely upon a smooth part
provided at the extremity of the mandril. The lever arın Ñ' also carries a small
pawl O, which is capable of assuming different positions and of engaging in the teeth
of the cutter so as to divide the teeth properly. From the foregoing it will be
observed that the apparatus carrying the cutters is composed of a number of parts
which enable the cutter to be brought with facility under the action of the grind-
stone, whatever may be its dimensions or shape or the inclination of its teeth, and
that the generating line of the tooth may always be brought parallel to the
direction of the motion of the carrier J, which, as herein-before described, effects
the displacement of the cutter longitudinally during the operation of grinding or
sharpening.
In order to grind or sharpen cutters having a non-perforated stem, and which
consequently cannot be mounted on the mandril or cutter holder herein-before
described, the modification of holder illustrated in Figures 4 and 5 is adopted.
P is the body of the holder which is attached to the rod N in lieu of the arm N',
and fixed in the proper position by means of a set screw q. The front part p pro-
vided with a V shaped notch at 4, is jointed to the body P at the point o, and
secured thereto by a screw; and to the body P is also attached a spring p' which

page_text: is placed with a concavity at 5, with which it is provided, situate immediately above
the notch 4 in the part p.
The mandril t is replaced by a small adjustable eccentric centre which supports
the centre of the cutter R to be ground or sharpened, whilst the stem 6 of the latter
lies in the notch 4 of the holder p, where it is adjusted on its true centre.
The
grinding or sharpening operation is then carried out in the same manner as with a
cutter mounted on a mandril t. This arrangement is equally applicable to the
grinding or sharpening of rimers and all tools which are not perforated at the
centre.
Figures 6 and 7 represent in front sectional elevation and side elevation respec-
tively the positions of the cutter R and the grinding stone or disc d when n
cylindrical cutter is being subjected to the grinding or sharpening operation, in
which case the grinding or sharpening action takes place in a direction at right
angles to the cutting edge, that is to say, that every part of the grinding disc or
stone d, rotating in the direction indicated by the arrow, acts successively on
the edge of the tooth whilst the cutter R moves longitudinally so as to present
every portion of the tooth in succession to the action of the disc or stone.
Figure S shows the relative positions of the grinding disc or stone d and cutter R
when operating on conical cutters with straight teeth; during the grinding or
sharpening process the generating line of the cone is placed horizontally, and the
grinding disc or stone acts in the same direction and in the same manner as when
operating on a cylindrical cutter.
Figure 9 represents the positions of the grinding disc or stone d and cutter R
when operating on a cutter with radiating teeth at right angles to its axis; the
cutter is placed with its axis vertical and the teeth upwards so as to partake of the
motion of the carrier. The grinding or sharpening operation is then effected in the
same manner as with cylindrical cutters.
Figure 10 illustrates the positions of the grinding disc or stone d and cutter R
when operating on a conical cutter with inclined teeth. The arrangement is similar
to that employed for the conical cutter with teeth in the same plane as the axis,
but the cutter holder is suitably inclined so as to present the edges of the teeth at
right angles to the motion of the grindstone or disc.
Figures 11, 12, and 13 show different positions assumed during the process of
grinding or sharpening by a dentated rotating cutter with curved teeth. The
cutter is first placed on the holder on the lever arm N¹ and the screw m' which
holds the spindle in the split sleeve m is then loosened, and by means of the
crank handle M. rotary motion is imparted to the spindle n, and consequently to
the cutter R.
By adjusting the cutter in such a manner as to cause the mean centre of the
curves of the teeth to correspond with the centre of rotation of the spindle which
carries the cutter, and then moving the oscillating frame carrying the grinding disc
by hand by means of the lever f, and turning the crank handle M, the cutter will
be ground or sharpened, according to its shape, by following the curves with the
lever so as not to injure the profile of the cutter.
When operating on a cylindrical cutter with helical teeth, the pawl O is dis-
pensed with, and in liou thereof a pawl O' (Figure 14) is employed, the same being
secured to the stationary support F by means of a pin or centre inserted in a
hole s, Figure 1.
It will be observed that on changing the position of the cutter by means of the
slide J, the tooth slides over the stationary pawl 01 (Figure 1), which will impart
to the cutter a rotatory motion corresponding to the inclination of the teeth or pitch
of the helix.
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 therefor claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-

page_text: First. The system or mode of grinding or sharpening cutting tools of the descrip-
tion herein-before referred to, by operating in a direction at right angles to the
cutting edgo of the same, substantially as herein-before described.
Second. The employment of a device or appliance so arranged as to admit of
the cutting tool being supported at any required angle, substantially as herein-before
described.
Third. The employment of a balanced adjustable or oscillating frame carrying
the grinding disc or stone, and so arranged as to be capable of being moved upon
an axis or of being maintained stationary, according to the nature of the work to
be performed, substantially as hercin-before described.
In witness whereof, I, the said John Henry Johnson, have to this my
Specification set my hand and seal, this Seventeenth day of April, One
thousand eight hundred and seventy-eight.
J. HENRY JOHNSON. (L.S.)