Improvements in Drill Grinding Machines.
Year: 1890

page_text: Date of Application, 25th Apr., 1890
Complete Specification Left, 24th Feb., 1891-Accepted, 11th Apr., 1891
PROVISIONAL SPECIFICATION.
Improvements in Drill Grinding Machines.
A. communication from abroad by MILNER PRINCE HIGGINS and CHARLES HILL
MORGAN, both of Worcester, in the State of Massachusetts, one of the United
States of America, Mechanical Engineers.
I, ALFRED GEORGE BROOKES, of the firm of Wm. Brookes & Son, of 55 & 56,
Chancery Lane, in the County of Middlesex, Patent Agent, do hereby declare the
nature of this invention to be as follows
The invention relates to drill grinding machines, but more particularly to that
class called twist drill grinders, the object being to simplify their operation, and to
produce improved results. To these ends the invention consists of the construction
and arrangement of the novel mechanism.
In grinding a drill, the usual method employed in presenting it to the grinding
wheel is the swinging method, where the drill is held in a drill holder which is
arranged to swing upon an axis. The said axis not being coincident with the center
line of the drill, as it lies in the holder. The drills are held so that the ends to be
ground all extend beyond this axis toward the grinding wheel, the ground surface
obtained being a curved surface with the said axis for a centre, and the radius of the
curve always depending upon the distance of the end of the drill, from said axis, which
is obvious. It is also obvious that drills of different diameters cannot well be ground
to curves of the same radius. It follows then, that a machine to grind drills properly
should have some means of measuring the adjustment of the drill holder, away from the
axis, corresponding to the size of the drill to be ground. A graduated scale, with a
pointer arranged to move along the same, has been employed to accomplish these
ends. This system is faulty, inasmuch as it requires the machine operator to
determine the size of each drill before grinding, which is very often difficult to
accomplish, as many drills are not marked and would require measuring in order
to determine their sizes.
:1
In the invention, the proper adjustment of the drill holder is obtained by means
of an improved device which performs the operation of simultaneously calipering
drill, and giving the drill holder the proper adjustament for the same. To accomplish
this place the drill between the jaws of a peculiar shaped gauge attached to the drill
holder, making each drill adjust the machine according to its diameter. Other
improvements accomplished in this improved drill grinding machine are, a combina-
tion with the drill holder of a convenient truing device to maintain the truth of the
grinding wheel, an adjustable stop to limit the oscillating movement of the drill in
grinding, and an improved device to provide. for the holding and accurate grinding
of drills constructed with two or more cutting lips, including flat drills, and drills
with either straight or spiral grooves.
The apparatus embodies a main standard of the machine, and grinding wheel.
Three main parts with their attachments constitute the drill holder, which is held
in place in the main standard, by means of the clamping screw, which compresses a
split hub on the standard, and binds the sleeve portion, of the drill holder to any
part of its length, so that its longitudinal position may be rapidly adjusted.
A collar fastened to the sleeve, by set screw, may be adjusted. A ball handle is
attached to the inclined head which forms one end of the sleeve. This inclined
head is bored for the reception of a shaft, forming a part of the oscillating bracket.
This shaft extends below the bottom of the inclined head, and upon the end thus
protruding is mounted a collar, adjustably fastened by a set screw, and having an
upward projecting finger, attached to its periphery, and which extends above

page_text: sufficiently to come in contact with another projection, upon the inclined head
of the sleeve, when the collar is made to rotate with the oscillating bracket.
Another projection upon the oscillating bracket, similarly comes in contact with
a second projection upon the top of the inclined head. These projections, form
a positive stop to limit the oscillating movement of the bracket in one direction
whilst in the other direction it is limited by the adjustable projection a necessary
requirement in grinding drills of more than two cutting lips.
Upon the top of the oscillating bracket is mounted the drill holder top
adjustably fastened by the clamping screw adjustable to and from the emery
wheel when the screw is loosened.
A longitudinally adjustable support for the shank of the drill, is provided
held by a screw working through a slot in the drill holder top.
The drill stop is similarly adjusted, and fastened by screw; portions of the
drill stop are also relatively adjustable.
A sleeve passes through a split hub at the top of the main support of the
drill stop and is adjustably clamped by means of a screw.
The spindle, has a longitudinal movement in the sleeve and is operated against
the end of the drill by means of a thumb screw, for the purpose of feeding the
drill against the grinding wheel.
The end of the drill holder top toward the grinding wheel is provided with
a lateral projection, through which is bored a hole for the reception of the
wheel truing device adjustably held in place by the set screw; this truing
device may be an ordinary diamond set in a cylindrical holder, or any other
instrument suitable for truing emery wheels.
One jaw of the adjusting gauge is attached to, and forms a part of the drill
holder top, whilst the other jaw is attached to the oscillating bracket, and is
therefore stationary while the other part is moved along with the drill holder
top, in adjusting the same for a drill.
The drill holder top, does not move at right angles to the axial line of
oscillation. And in order to move the end of the drill a certain distance beyond
the axis, the drill holder top must be moved a still greater distance.
To change the direction of the adjustment so that it shall be at right angles
or at other angle with a given axial line, a modification of the adjusting gauge
is necessary.
An adjustable lateral support is used for holding four lipped drills and flat
drills in a V shaped holder. A. thin piece of steel plate working through a slit
in the side of the drill holder top, may be placed flush with the inner surface
of the holder, moved up to support the drill upon one side, the device being
held in place, in each position by set screw. Unless the oscillating movement
of the drill holder top, and the drill is limited, the drill lips would come in
contact with the grinding wheel, when swung far enough in that direction. The
adjustable stop previously explained, is designed to obviate this difficulty.
The operation of the improved drill grinder is as follows
The clamping screw is first loosened and the drill holder is drawn out at a
distance away from the grinding wheel. The clamping screw, is then loosened
and the drill holder top moved until the drill to be ground will pass between
the jaws of the adjusting gauge. The drill holder top is thus properly adjusted
for the diameter of the drill, and is then rigidly clamped to the oscillating
bracket by the screw. The drill is then placed in the V shaped supports of
the drill holder with the lip to be ground extending slightly beyond the lip rest,
with the edge of the groove of the drill resting against it. The drill stop, is
then moved up against the shank end of the drill, and clamped by means of the
screw. The clamping screw, is now loosened, and the whole drill holding device
is moved up until the point of the drill nearly comes in contact with the
grinding wheel, then the clamping screw is tightened.
The drill is now held in position with one hand, while with the other the drill
is fed to the grinding wheel by means of the thumb screw, acting against the

page_text: end of the spindle, and the drill holder top and guide bracket, are at the same
time oscillated to the right and left against the stops, as previously explained.
The oscillating portion of the drill holder works about the axial line, which
movement may be in a helical direction, toward the grinding wheel, to give the
proper clearance to the drill, or the drill may be so held, that its centre line
prolonged would never meet the axial line of oscillation thus a ground surface
being obtained eccentric with the drill, the necessary backing off (or clearance)
would be obtained.
To true up the grinding wheel, the truing device is adjusted at a suitable
distance beyond the end of the drill holder, and is fastened by means of the.
set screw. The drill holder is now moved up until the truing device will touch
the lowest surface of the wheel, then the collar, is fastened in contact with the
hub of the main support, by means of the set screw.
.
The clamping screw, being left loose, with one hand grasping the ball handle,
and with the other holding the oscillating portion of the drill holder against the
stop on the left hand, the whole drill holder is swung about the centre of the
sleeve, the collar, keeping the sleeve in place by its continuous contact with
the casting.
The truing device, thus passes across the grinding wheel, on a plane, and by
When not in use,
its cutting action, accurately trues the surface of the wheel.
the truing device is pushed back & fastened out of the way of the set screw.
Dated the 25th day of April 1890.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Drill Grinding Machines.
A communication from abroad by MILNER PRINCE HIGGINS and CHARLES HILL
MORGAN, both of Worcester, in the State of Massachusetts, one of the United
States of America, Mechanical Engineers.
I, ALFRED GEORGE BROOKES, of the firm of Wm. Brookes & Son, of 55 &
56, Chancery Lane, in the County of Middlesex, Patent Agent, do hereby declare
the nature of this invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
The invention relates to drill grinding machines, but more particularly to that
class called twist drill grinders, the object being to simplify their operation and to
produce improved results. To these ends the invention consists of the construction
and arrangement of the novel mechanism hereinafter fully described.
In grinding a drill, the usual method employed in presenting it to the grinding
wheel is the swinging method, where the drill is held in a drill holder which is
arranged to swing upon an axis. The said axis not being coincident with the
centre line of the drill, as it lies in the holder. The drills are held so that the
ends to be ground all extend beyond this axis toward the grinding wheel, the ground
surface obtained being a curved surface with the said axis for a centre, and the
radius of the curve always depending upon the distance of the end of the drill,
from said axis, which is obvious. It is also obvious that drills of different diameters
cannot well be ground to curves of the same radius. It follows then, that a machine
to grind drills properly should have some means of measuring the adjustment of the
drill holder, away from the axis, corresponding to the size of the drill to be ground.
A graduated scale, with a pointer arranged to move along, the same, has been
employed to accomplish these ends. This system is faulty, inasmuch as it requires
the machine operator to determine the size of each drill before grinding, which is
very often difficult to accomplish, as many drills are not marked and would require
measuring in order to determine their sizes,

page_text: In the invention, the proper adjustment of the drill holder is obtained by means
of an improved device which performs the operation of simultaneously calipering
a drill, and giving the drill holder the proper adjustment for the same.
To
accomplish this place the drill between the jaws of a peculiar shaped gauge
attached to the drill holder, making each drill adjust the machine according to
its diameter.
Other improvements accomplished in this improved drill grinding machine are, a
combination with the drill holder of a convenient truing device. to maintain the
truth of the grinding wheel, an adjustable stop to limit the oscillating movement
of the drill in grinding, and an improved device to provide for the holding and
accurate grinding of drills constructed with two or more cutting lips, including
flat drills, and drills with either straight or spiral grooves. These various
improvements I will now proceed to explain, with the aid of the accompanying
drawings, in which like figures and letters of reference indicate the same parts
in each.
Fig. 1 is a part section and eleavtion of the drill grinding machine with a small
drill in place, showing the method of setting the drill holder by means of a
graduated scale.
The graduated scale being disclaimed in this Application.
Fig. 2 is an elevation of the same style of drill holder, and with the emery
wheel, is shown detached from the machine, and shows a larger drill in place.
Fig. 3 is an elevation of the drill holder, showing the operation of my new
adjusting gauge.
Fig. 4, is an elevation similar to Fig. 3.
Figs. 5 and 6, are plan views of the drill holder, showing the adjusting gauge
more clearly.
Fig. 7, is a diagram explaining the principles of the adjusting gangé.
Fig. 8, is an elevation of the drill grinding machine, illustrating the operation
of the truing device.
Fig. 9, is an elevation of a portion of the drill holder drawn apart, to illustrate
the action of the adjustable stop.
Fig. 10, is an end view of the drill holder, showing an
drill in place.
ordinary two-lipped twist
Fig. 11, is a similar view, showing a three lipped drill in place.
Fig. 12, is an end view of the drill holder, and shows the method of holding
a four lipped drill in the V shaped holder, by means of an adjustable lateral
support.
Fig. 13, is a view similar to the three preceding and shows the method of holding
a flat drill in place.
A. is the main standard of the machine, a the grinding wheel. The parts, B, D,
and C, with their attachments constitute the drill holder,which is held in place in
the main standard, A, by means of the clamping screw A¹, which compresses
a split hub on the standard, and binds the sleeve portion, B, of the drill holder
to any part of its length, so that its longitudinal position may be rapidly
adjusted.
B is a collar fastened to the sleeve B, by the set screw b, and may be adjusted at
pleasure.
B2 is a ball handle attached to the inclined head which forms one end of the
sleeve, B. This inclined head is bored for the reception of a shaft forming a
part of the oscillating bracket C.
The centre of this shaft is represented by the axial line a y. This shaft extends
below the bottom of the inclined head, and upon the end thus protruding is
mounted a collar, C, adjustably fastened by a set screw c, and having an upward
projecting finger, 2 attached to its periphery, and which extends above sufficiently
to come in contact with another projection, 2 upon the inclined head of the sleeve B,
when the collar is made to rotate with the oscillating bracket. Another projection e¹
upon the oscillating bracket C, similarly comes in contact with a second projection &

page_text: upon the top of the inclined head. These projections, c' and form a positive
stop to limit the oscillating movement of the bracket C in the direction to the
left, while the movement to the right being limited by the adjustable projection c²
permits an adjustable limitation of the oscillating movement toward the right
hand, which is a necessary requirement in grinding drills of more than two cutting
lips.
Upon the top of the oscillating bracket C is mounted the drill holder top D
adjustably fastened by the clamping screw D' and arranged to be adjusted to and
from the emery wheel when the screw D is loosened.
D is a longitudinally adjustable support for the shank of the drill held by
screw D³ working through a slot in the drill holder top D..
E is the drill stop similarly adjusted and fastened by screw E²; e E' and e¹ are
adjustable portions of the drill stop.
The sleeve E passes through a split hub at the top of the main support of the
drill stop E and is adjustably clamped by means of the screw e
The spindle, e has a longitudinal movement in the sleeve El and is operated
against the end of the drill by means of the thumb screw e, for the purpose of
feeding the drill against the grinding wheel. The end of the drill holder top D
toward the grinding wheel is provided with a lateral projection, through which is
bored a hole for the reception of the wheel truing device adjustably held in place
by the set screw 2; this truing device may be an ordinary diamond set in a
cylindrical holder, or any other instrument suitable for truing emery wheels.
The dotted lines in Figure 8 show another position assumed by the drill holder
in passing across the emery wheel while truing the same, which operation will be
fully explained farther on.
In Figs. 1 and 2 are shown the different positions of the ends of the different
sized drills from the axial line, a y, and the said figures also show the method of
adjusting the drill holder top by the graduated scale system. Fig. 3 shows the
same adjustment as in Figure 1, but is accomplished by means of my new adjusting
gauge. Fig. 4 shows the same adjustment as in Fig. 2 also by means of the
adjusting gauge. D and C are the jaws of the. adjusting gauge, and are more
fully understood by referring to Figs. 5 and 6.
D is attached to and forms part of the drill holder top, D, and C is attached to
the oscillating bracket, C, and is therefore stationary while D is moved along with
the drill holder top, in adjusting the same for a drill. The edges of drill contact of
these gauge jaws in this case are approximately parallel, and their angularity
with the line of movement of the drill holder top, depends upon the requirements
of the machine.
The drill holder top D it will be seen, does not move at right angles to the axial
line of oscillation . y. It follows, then, that in order to move the end of the drill a
certain distance beyond the axis, the drill holder top must be moved a still greater
distance. It is possible, however, to change the direction of the adjustment so that
it shall be at right angles or at other angle with the axial line, ay, in which case a
modification of the adjusting gauge above shown would be necessary as will be
shown farther on. It having been determined by the construction of the machine,
that the drill holder top needs to be moved along its line of movement three inches
when the drill to be ground is two inches in diameter, it is obvious that the ratio of
adjustment to the diameter of the drill is as (32) with this proposition, as a
starting point the explanation of the diagram shown in Fig. 7 is as follows. The
line O, O represents the edge of drill contact of the gauge jaw C, and must be
conceived as stationary. The line NN, and the dotted line, M¹ M, represent
different positions of the edge of drill contact of the gauge jaws D, as it is adjusted
in the direction O, M corresponding to the line of movement of the drill holder top.
Conceiving the lines, N', N, and O, O to be in contact at the start, adjustment of
the distance from O to N say 14 inches, will bring the lines O¹, O and N', N a
certain distance apart, measured by the perpendicular line O, L, the length of which
must be one inch because 11:32 according to the proposition above

page_text: mentioned. If now the line, N¹, N, is again adjusted a distance N, M, equal to O, N,
it is obvious that the distance N, L will be equal to the distance O, L, and the
drill calipered by the lines M, M and O, O will be two inches in diameter or twice
the distance, O, L, while the distance O, M, (corresponding to the whole adjust-
ment of the drill holder) will be twice the distance, O, N, or three inches, which
conforms to the ratio assumed. It is obvious that any drill calipered by the gauge
jaws will adjust the drill holder top in the same ratio, as above demonstrated. It
is also obvious that any difference in the angle of the lines (01, 0,) and N', N with
the line of adjustment, O, N, would change the ratio of adjustment to the diameter
of the drill, and if the said lines, O', O, and N', N, were at right angles to the line
of adjustment O, M, the ratio would be unity, and the adjustment would equal the
diameter of the drill. If the lines of drill contact, of the gauge jaws D₁ and C
represented by the lines O¹O and NN of the diagram Fig. 7 were other than
parallel for instance inclined toward each other, the required result could be
obtained but the drill would have a third point of contact, i.e. against the side of
the drill holder top, and the drill would have to be withdrawn longitudinally. In
a drill grinder where the adjustment of the drill holder top is at, or near, a right
angle to the axial line of oscillation, the adjustment might be less than the diameter
of the drill, in which case the end of the gauge jaws should diverge and form a V
when closed together. I do not therefore, confine myself to any particular ratio of
adjustment of drill holder, nor to a particular angle of gauge jaw.
In Fig. 10, T is shown an ordinary twist drill held in correct position by the lip
resti, fastened to the V shaped holder by the screws, S. The lip rest, i, is dis-
claimed in this application.
In Figs. 12 and 13 are shown the functions of the adjustable lateral support, I,
for holding four lipped drills and flat drills in a V shaped holder.
I is a thin piece
of steel plate working through a slit in the side of the drill holder top, and may be
placed flush with the inner surface of the holder, as in Fig. 10, or as in Fig. 12
moved up to support the drill upon one side, the device being held in place, in each
position by the set screw J shown in Fig. 6.
In Fig. 13, the support is placed upon the opposite side of the drill, from the
position in Fig. 12. By a reference to Figs. 11 and 12 it will be seen that unless
the oscillating movement of the drill holder top, and the drill is limited, the drill
lips T and T would come in contact with the grinding wheel, when swung far
enough in that direction. The adjustable stop C², previously explained, is designed
to obviate this difficulty.
The operation of the improved drill grinder is as follows:-The clamping
screw Ais first loosened and the drill holder is drawn out at a distance away from
the grinding wheel. The clamping screw, D2, is then loosened, and the drill holder
top moved until the drill to be ground will pass between the jaw C and D of the
adjusting gauge. The drill holder top is thus properly adjusted for the diameter
of the drill, and is then rigidly clamped to the oscillating bracket, C by the
screw D. The drill is then placed in the V shaped supports of the drill holder
with the lip to be ground extending slightly beyond the lip rest, i, with the edge of
the groove of the drill resting against it. The drill stop E is then moved up against
the shank end of the drill, and clamped by means of the screw E. The clamping
screw A¹ loosened, the whole drill holding device is moved up until the point of the
drill nearly comes in contact with the grinding wheel, then the clamping screw A',
is tightened. The drill is now held is position with one hand, while with the other
the drill is fed to the grinding wheel by means of the thumb screw el, acting against
the end of the spindle, e, and the drill holder top D, and guide bracket, C, are at
the same time oscillated to the right and left against the stops, as previously
explained.
The oscillating portion of the drill holder works about the axial line ay which
movement may be in a helical direction, toward the grinding wheel, to give the
proper clearance to the drill, or the drill may be so held (by the construction of
the machine) that its centre line prolonged would never meet the axial line of

page_text: oscillation, thus a ground surface being obtained eccentric with the drill, the
necessary backing off (or clearance) would be obtained. These and various other
methods of obtaining clearance are disclaimed in this Application.
To true up the grinding wheel, the truing device is adjusted at a suitable
distance beyond the end of the drill holder, and is fastened by means of the set
screw. The drill holder is now moved up until the truing device will touch*
the lowest surface of the wheel, then the collar, B¹, is fastened in contact with
the hub of the main support, A, by means of the set screw, b.
The clamping screw A', being left loose, with one hand grasping the ball
handle, B2, and with the other holding the oscillating portion of the drill holder
against the stop on the left hand, the whole drill holder is swung about the
centre of the sleeve, B, the collar B¹ keeping the sleeve in place by its con-
tinuous contact with the casting, A.
The truing device f¹, thus passes across the grinding wheel, in a plane, and
by its cutting action, accurately trues the surface of the wheel. When not in
use, the truing device is pushed back and fastened out of the way by the set
Screw f, as shown in Figs. 3 and 4.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination with a twist drill grinding machine, of the drill holder
top, D, and the oscillating bracket, C, provided respectively with the projecting
gauge jaws D and C, arranged to simultaneously caliper the drill to the ground,
and to axially adjust the drill holder as above set forth.
2. In a twist drill grinding machine the combination with a V grooved drill
holder of the parallel gauge jaws D', and C, whose contact-faces are inclined
to the line of their adjustment, for the purpose above described.
3. The combination with the drill holder top, D, and oscillating bracket, C,
of the adjustable stop c², arranged to limit the oscillating movement of the drill
holder, as, and for the purpose set forth.
4. The drill holder top D and the oscillating bracket C, mounted upon the
sleeve B, combined with the adjustable collar B', and the emery wheel truing
tool, for the purpose described.
5. The combination of the main supporting standard A, with the emery wheel
truing tool, ƒ¹, suitably mounted upon, and swinging with the sleeve, B, for the
purpose set forth.
6. The combination with the drill holder top D, mounted upon the oscillating
bracket, C, of the adjustable stop, c², and the lateral drill support, I, arranged as
and for the purpose above described.
7. An oscillating drill holder provided with a lip rest, i, combined with the
adjusting gauge jaws D and C, the oscillating bracket C, and the adjustable
stop, as and for the purpose set forth.
Dated the 22nd day f
1901
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.