IMPROVEMENTS IN DRILLS AND IN APPARATUS FOR SHARPENING DRILLS
Year: 1883

page_text: "
LETTERS PATENT to John Henry Johnson of 47 Lincolns Inn Fields in the
County of Middlesex Gentleman for an Invention of "IMPROVEMENTS IN
DRILLS AND IN APPARATUS FOR SHARPENING DRILLS Communicated to him
from John Sellers Bancroft and William H. Thorne persons resident in the
City and County of Philadelphia Pennsylvania United States of America
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 9th January 1883.
">
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN DRILLS AND IN APPARATUS FOR SHARPENING
DRILLS a communication to me from abroad by John Sellers Bancroft and
William H. Thorne of the City and County of Philadelphia Pennsylvania, United
States of America
To drill true holes which shall all have the same diameter and also the closest
approximation to the size of the drill it is necessary that the two cutting edges or
lips of the drill should be of precisely the same length and at the same angle with
the axis of the drill and to obtain the greatest drilling effect it is requisite that the
backing or clearance of the two lips should conform as closely as possible near the
cutting edge to the shape of the bottom of the hole produced by the drill so as to
give the greatest strength and support to the cutting edges, while giving sufficient
Clearance to enable the drill to cut freely without binding. As the shape of the
bottom of the hole is a right cone with the apex truncated by the point of the
drill it will be evident that the best shape for the end of the lip of a drill will be.
that of the surface of a right cone baving its axis sufficiently eccentric to the axis
of the drill to give the proper clearance to the edge.
One object of this Invention is to shape the cutting end of a drill so as to
increase its efficiency and durability it is a further object of the Invention to hold
a drill to be sharpened accurately in the true position without requiring especial
skill on the part of the operator it is a further object of the Invention to simplify
the construction of drill-sharpening machines and to obviate the defects caused by

page_text: wear; it is a further object of the Invention to provide a continuous supply of
water to the grinding wheel by mechanism that shall be at once simple and
durable; it is a further object of the invention to introduce the water to the
grinding wheel in such a manner that it shall reach the wheel at that point in its
revolution where it operates upon the drill and to these ends the nature of the
invention consists in mechanism for grinding tho end surface of each lip of the
drill to a right cone or to a conical surface the apex of which cone or conical
surface is beyond the point of the drill while its axis is not parallel to nor does it
meet the axis of the drill and it further consists in providing the requisite
clearance back of the cutting edge by adjusting the angle of the axis of this cone
with reference to the axis of the drill and its position with reference to the cutting
edge; and it further consists in fixing this angle and this position at their best
conditions in the construction of the machine so that they can not be effected
thereafter by tho want of skill in the workman; and it further consists in
supplying water to the grinding wheel by incans of a cord or belt pump; and it
further consists in providing a shield which receives the water from the belt-
pump, and delivers it upon the wheel only at that point where it operates upon
the drill.
The rationale of this Invention is as follows:-
Suppose a hollow right cone to be revolving about a horizontal axis and its
interior surface to be provided with some abrading substance and that the lips of a
drill are inserted into this cone in auch manner that the axis of the drill shall;
coincide with that of the cone it will be evident that the end of the drill would be
shaped to a right cone but would not have the proper shape for cutting as the
centre of the drill would be a point which would only enter any material to be
drilled by punching or abrasion while the lips back of the edges of the drill would
have no clearance and hence tho drill would merely rub without cutting. Now
suppose one edge of a lip of this drill to be horizontal, move the drill away from
the axis of the abrading cone on a horizontal line and at the same time lower the
drill so that the cutting edge will be slightly below the centre of the cone and
present the drill against the abrading cone in this position the back of the lip will
be ground away first until the cone touches the cutting edge; if the drill is now
withdrawn and turned half round and the other lip presented in the same position.
it will result that the end of each lip will be ground to the shape of a right cone
and the point of the drill will be convex like a bow drill for cutting in both
directions being formed by the intersection of the cones forming each lip; this
gives the best possible shape for the drill point, and the clearance will evidently be
exactly adapted to the shape of the bottoin of the hole to be produced by the drill.
The distance that the centre of the drill is moved from the apex of the cone
depends upon the thickness of the central part of the drill and to avoid excessive
clearance on the outside of the drill-lip. it is found advantageous in practice to
reduce the inclined angle of the hollow cone so that the radius of the cone where
it touches the outside corner of the drill-lip is but little greater than the radius of
the drill itself for the largest drill the machine is intended to grind; this requires
that the axis of the drill shall not be coincident with nor parallel to the axis of the
grinding cone, and it follows that the clearance of the drill-lip will increase
slightly from the outside corner of the cutting edge to the point of the drill.
The shape of the end of the lip of the drill will be part of the surface of a right
cone the axis of which is coincident with that of the grinding cone and it is
evident that the same shape of lip would be produced if the grinding cone was
stationary and the drill was revolved not about its own axis but about the axis of
the grinding cone; and it follows that the same shape would be produced by a
grinding wheel the cutting surface of which is tangent to a side of this grinding
cone, and arranged to swing about the axis of this cono the drill in this case being
stationary; and conversely the grinding wheel can be arranged so as to revolve 5
about a fixed axis with its cutting surface tangent to a side of the right cone to
which the end of the drill-lip is to be formed the drill in this instance being

page_text: revolved or swung about the axis of this cone; these methods will all produce
precisely the same form of end to the lip of a drill and as the method last
described has many mechanical and practical advantages represents a machine
constructed on this plan.
The drill is held in position for sharpening its lip against a grinding wheel a
chuck is provided having two jaws sliding freely in grooves in the face of the
chuck and held in place by a ring under which they slide easily, being moved in
and out for the purpose of clamping the drill by means of a hand wheel which is
provided on its inner face with a scroll thread which fits and engages with a
corresponding scroll thread on the jaws; a hand wheel is held in position by n
flange on the aforesaid ring. Projecting from the back of the chuck, is a rod, which
carries a cross-head, provided with a centre pivot, which is concentric with the
centre of the chuck. The said rod has a key-seat extending its entire length in
which slides a feather secured in the cross-head; this keeps the centre-pivot always
in the line of the centre of the chuck; the cross-head is clamped to the rod in any
desired position by a screw. The centre pivot carries the end of the drill the front
end being clamped firmly close to the edge of the lips by the aforesaid jaws; the
position of the drill-lips in these jaws is determined by stops against which the
lips of the drill are rotated by hand before clamping; the position of the drill
end ways that is, the distance that the end of the lip projects from the face of the
chuck, is determined by another stop in one of the jaws. These three stops
determine the exact position of the lips of the drill with reference to the grinding-
wheel and the axis about which they are swung and as the jaws seize the drill
close to the lips and by a short bearing only there is no danger of springing any
drill to be sharpened. The chuck is formed with a shaft or arbor, projecting from
it, and which is fitted so as to turn freely in bearings formed with or secured to the
stand. The said shaft is formed with a shoulder and provided with a bolt and
washer at the outer bearing so that it has no end play; the chuck and with it the
drill can be rotated about the axis of the shaft by means of a lever which is formed
with a counterweight for the purpose of balancing the weight of the drill the
lower bearing of the shaft is provided with stops to limit the rotation of the chuck
in each direction.
The axis of rotation of the chuck makes an angle with the axis of the chuck
itself and also with the cutting face of the grinding wheel; if the grinding wheel
be driven and the chuck swung in its bearings it follows that anything held in tho
chuck and against the grinding wheel will be ground to the shape of a right cone,
the axis of which is the line of the axis of the shaft of the chuck. If the chuck be
now swung in its bearings by moving the lever towards the stop on the lower
bearing the end of the lip of the drill will be ground to the shape of a right cone
the axis of which is the aforesaid line of the axis of the chuck shaft and the apex
is the point where the said line is cut by the face of the grinding wheel; and as
the cutting edge of the lip is nearly on the same plane with the said axis the axis
of the drill and chuck being further below it, it follows that the end of the lip will
have a regular clearance back of the cutting edge and by trial a relative position
will be found for the axes of the shaft and drill and chuck and the stops of the
jaws which will give the combination of the greatest strength of lip with the most
efficient cutting edges; this position is determined in the construction of the
machine and the operator has only to bring the lips of the drill against the stops,
before clamping the drill in the chuck, to ensure the constant production of the
best shapes. When one lip of the drill is ground the jaws are released by turning
the hand-wheel and the drill is turned half way round until the opposite lips como
against the stops the drill being held against the back centre and clamped in this
position; if the chuck is now swung in its bearings the second lip of the drill will
be ground to precisely the same length as the first lip and will have precisely the
same angle and clearance and the drill will then produce a hole as nearly as
possible to its own diameter.
The centre lines of the two jaws are not in one line but are inclined to each

page_text: other to compensate for the difference in thickness of the centres of large and
small drills.
The jaws move in a plane at right angles to the axis of the drill so that one of
the stops always remains at the same distance from the face of the chuck. From
this it results that the point or centre of the drill will vary in its distance from
the chuck according to its diameter, the point of the small drills being much
nearer to the chuck and hence nearer to the axis of the chuck shaft this brings
the point or centre of the drill nearer to the apex of the cone in one direction
and the angle of the jaws above described brings it closer in the other direction
hence small drills are sharpened to a curve of smaller radius than the large drills
and all drills will have the same correspondence to the shape of the end of the
hole produced the curvature in all cases being proportioned to the diameter of the
drill and both these movements are made automatically without depending upon
the skill of the operator. The annular grinding-wheel is fastened to a plate
secured to or formed on a shaft which is fitted so as to revolve freely in a bearing
in a vibrating-frame which is secured to the shaft. The shaft turns and slides
freely in bearings formed on the mainpost of the machine and carries pulleys;
One of these pulleys is secured to the hub of a large pulley which runs loose on
the shaft and drives the grinding wheel by another pulley secured to the shaft of
the grinding wheel carrier; a bearing is provided with a screw-thread at one end
in which the screwed hub of a hand-wheel fits; the shaft carrying the driving
pulleys is forced against the hub of the hand-wheel by a counter weight secured
to a shaft to which is also secured a lever which presses against a hub or bearing
on the bottom of the vibrating-frame the said hand wheel moves the shaft of the
driving pulleys and with it the said frame carrying the grinding wheel in one
direction and the counter weight moves it in the other and at the same time takes
up all lost motion; the said shaft thus serves as a counter-shaft to carry the
driving-pulleys as a slide rest to move the grinding wheel against the drill and as
a hinge or pivot for the frame which for the purpose of keeping the cutting face
of the grinding wheel true and free from ridges is vibrated back and forth by a
bell crank lever which is pivoted to the side of the frame, the end of a lever fits
in a groove or recess in an arm which projects from the main post as .the said
lever is raised and lowered by the operator its said end works within the groove
in the said arm as a gear tooth works in a rack and so moves the vibrating frame
back and forth carrying the grinding-whcel past the end of the lip of the drill and
thus keeps the face of the wheel true. The weight of the vibrating frame being
almost entirely to one side of the shaft keeps the arm of the lever always against
one side of the groove and so takes up lost notion. When the machine is not in
use or when the drill is being changed the said lever rests against a projection on
the frame and so holds it from swinging too far back while if it be desired to
empty the tank which is formed in the frame a small pin may be withdrawn from
the fulcrum pin and the lever slipped sideways until it clears a projection on the
frame when the frame can be swung back and the water emptied. The stand of
the chuck and drill carrying parts is pivoted on top of the main post. A hook
bolt clamps the said stand to the main post and holds it securely in position a
projection from the said stand backs up the said hook-bolt and keeps it from
turning and at the same time strikes against the stops on the top plate of the
main post. These stops confine the motion of the stand within the angle to which
the machine is adapted to grind the end of the drill. By means of this adjustment
the drill may be sharpened with the two cutting edges forming an angle with each
other which experience has shown to be best adapted for general work or the stand
may be moved against the other stop and secured by the bolt and the edges of the
drill will then be ground at a much more obtuse angle with each other for the
purpose of drilling thin work such as steel rails or boiler work or the stand may
be clamped at any position between the stops so as to grind the end of the lips of
the drill to the angle best adapted to the particular work in hand. The stand is
provided with a ledge or raised rim all round it to retain the water which is

page_text: thrown on the drill and to return it into the vibrating frame which forms the
water tank from which the pump draws its supply.
The water is supplied to the drill to be sharpened by means of an endless belt
preferably perforated or roughened to increase the adhesion of the water this belt
is driven by a pulley which runs freely upon a stud firmly secured in the grinding
wheel-cover. This pulley is driven by two studs fastened in the front of the
grinding wheel plate; these studs enter freely into two holes drilled to receive
them in the pulley; this arrangement allows the wheel cover to be moved up as
the grinding wheel wears the pins or studs entering further into the holes in the
pulley. The necessary tension on the belt is provided by a lower pulley and frame
in which the pulley runs; the said frame slides freely in the pump-caso formed on
the front of the wheel-cover the lower end of the pump case being submerged in
the water in the tank. The upper side of the belt carries tho water up through
the pump case with such velocity that the water is thrown off the belt with great
force at the point where the belt begins to curve round the pump pulley; the upper
part of the pump case forms a shield to deflect this water and guide it so that it is
thrown on the grinding wheel through an opening. The inside of this shield is so
formed that the water thrown from the belt strikes against the surface of the
shield at a very acute angle so as to change the direction of the water gradually
without checking its velocity so that the greater part of the water lifted by the
belt is thrown forward and out of the said opening where it falls on the edge of the
drill being sharpened and against the grinding wheel. The wheel-cover which is
formed in one piece with the pump-case and deflecting shield covers the outside
of the wheel and its front, except where the end of the drill is presented to the
grinding-wheel; at this point an opening is made through the front plate just
large enough to receive the largest drill that can be ground; a part of the front
plate is also set back a short distance so as to clear the end of the drill when the
grinding wheel is moved by swinging the tank as before described. Owing to
the high velocity of the grinding wheel it is very important to prevent the
indraught of air to any great extent as this tends to break up the water and carry
it from the wheel in a fine spray, which would be very objectionable; to prevent
this the wheel cover is made to fit the wheel as closely as possible and there is a
large opening made in the bottom of the cover in the direction of rotation of the
wheel to allow the water that enters the case at the point where the drill is ground
to escape into the tank and also to give free vent to the air that may be drawn in
at any point. A small amount of water will be carried round by the grinding
wheel, and to prevent this water from being thrown off at the back edge
of the wheel-cover, inclined ribs are formed on the inside of the cover just above
the aforesaid large opening; these ribs serve to break up the adhesion of the
water to the wheel by forming eddies of air and their inclination serves to form a
slight indraught of air which prevents the water from reaching the back of the
cover with any velocity; the lower sides of these ribs act as drains, and a little
water runs from their outer ends falling into a drain which discharges into the tank.
The cover is held in place by studs, one of which studs is fitted tightly into the
tank the other fits tightly into the cover and slides freely in its bearings in the
tank; the bearing for the stud in the cover is split and can be closed so as to hold
the stud firmly by a binding screw so that the cover can be adjusted as the face of
the grinding wheel wears away so as always to deliver the water on the edge of
the drill and by releasing the binding screw the cover may be drawn completely
off for the purpose of cleaning or repairs.
From the foregoing description it will be seen that the mechanism above
described will produce upon a dy drill or twist drill a cutting edge shaped to a
right cone, the apex of which cone is beyond the point of the drill while its axis is
not parallel to nor does it meet the axis of the drill and the same result will attend
the operation of either of the several modifications described under the rationale of
the Invention.
It will be observed that throughout the foregoing specification I have described a

page_text: combination as producing a drill-lip having the contour of a right cone but the
advantages of the improvement may be availed of to produce a drill-lip having a
contour not strictly that of a right cone; thus, if the swinging mechanism for
holding and presenting the drill to the grinding surface should be arranged to
present the drill to the periphery of the grinding-wheel instead of to the side
thereof the traverse of the grinding wheel in this case to be parallel to this
grinding surface the axis of the grinding-wheel the line of contact with the drill at
the periphery of this wheel and the axis about which the chuck swings being in
the same plane, the resultant contour will be that of a right cone; but if the axis
about which the chuck swings should be inclined to this plane the surface produced
upon the end of the drill-lip would not be that of a right cone, because no
part of this surface would be in a right line but it would still be a conical surface
which would have the same clearance as the right cone I have described; I there-
fore do not limit myself to the production of a drill lip having the contour of a
right conc.

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
7th July 1883.
33
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN DRILLS AND IN APPARATUS FOR SHARPENING
DRILLS .a communication to me from John Sellers Bancroft and William
H. Thorne persons resident in the City and County of Philadelphia, Pennsylvania,
United States of America
To drill true holes which shall all have the same diameter and also the closest
approximation to the size of the drill it is necessary that the two cutting edges or
lips of the drill should be of precisely the same length and at the same angle with
the axis of the drill, and to obtain the greatest drilling effect, it is requisite that
the backing or clearance of the two lips should conform as closely as possible, near
the cutting edge, to the shape of the bottom of the hole produced by the drill, so as
to give the greatest strength and support to the cutting edges, while giving
sufficient clearance to enable the drill to cut freely without binding. As the shape
of the bottom of the hole is a right cone with the apex truncated by the point of
the drill it will be evident that the best shape for the end of the lip of a drill will
be that of the surface of a right cone having its axis sufficiently eccentric to the
axis of the drill to give the proper clearance to the edge.
The importance of sharpening drills by machinery has long been known and
numerous devices have been employed for the purpose but all of them heretofore
have been unsatisfactory both in the shape produced and in the means for holding
the drill. The shape or clearance of the cutting edge has been obtained in some
machines by rocking the drill, when held in a chuck about an axis parallel with
the edge to be ground; this is objectionable as giving a uniform and cylindrical
form of clearance over the whole length of the cutting edge. In this shape the
clearance can not be at the best angle at all points, but will be excessive at some,
and the edge of such places will be weak, so that the drill will wear irregularly
and require frequent sharpening. In other machines the drill is moved forward
by a cam while it is rocked about an axis parallel with the cutting edge. This
plan merely changes the shape of the lip from cylindrical to some other curve,
which, however, is still uniform over the whole length of the lip and is therefore
open to the same objection as the first. In some cases an attempt has been inade
to obtain the necessary clearance by rotating the drill about its own axis and at
the same time swinging it sideways, and also in some cases giving it at the same
time a slight forward movement by a cam. These devices are necessarily
complicated and expensive to manufacture, and difficult to keep in order, and
moreover are not adapted to drills of different diameters, while the resultant surface
is not that of a right cone, and hence the clearance produced is always excessive at
some points in the cutting edge.
All of the devices heretofore used for holding the drills while being sharpened
are objectionable as not defining the position of the cutting edge with sufficient
exactness. The chucks are usually adapted for twist drills only, and there is
nothing to limit the distance the drill may project from the chuck, which distance,
therefore, must depend upon the skill of the workman; but as each variation in
this distance produces a change in the curvature, and clearance of the cutting edge,
uniformity in shape is not practically attainable. Heretofore no adequate means
have been provided to define the position of the cutting edges with reference to any
given point in the chuck which rotates it, that is, the drill may be clamped in the

page_text: chuck so that the rotation of the latter may not produce any clearance, or it may
be excessive, or the highest point may even be back of what should be the cutting
edge. To avoid this trouble the drill has been laid in a grooved bed provided with
a projection for the purpose of fixing the position of the drill, one lip of the drill
resting against this projection while the opposite edge is being ground. This
device is evidently applicable only to twist drills, and any variation in the spacing
of the flutes in the drill will change the clearance of the two lips, while any
differences in the longitudinal position of the drill, will rotate the lips and thus
change the clearance materially. It is also evident that if the drill is not perfectly
straight the position of the point will vary as the drill is turned over, and that
consequently the two lips will vary in length and the drill will make a hole larger
than its own diameter.
In drill-sharpening machines a variety of devices have been employed for
applying water to keep the temper of the drill from being drawn; some machines
have the ordinary drip cup which requires constant attention to replenish it with
water, and this trouble results in diminishing the supply, so that this plan is but
little better than grinding dry. In other cases a pump (usually rotary) is used to
force the water up through hose to the grinding-wheel just above the drill; this
works well at first but the pump rapidly wears from the grit carried by the water
and is soon rendered useless.
The traverse of the grinding wheel necessary to keep its cutting face true and
free from ridges has been obtained in some instances by mounting tho wheel upon
a slide rest, which is traversed by a lever; this is expensive to construct, and
difficult to maintain in order, by reason of the grit which is a necessary consequence
of the grinding operation. In other cases the spindle of the grinding-wheel is
traversed in its bearings; this, though less expensive to construct wears much more
rapidly than the slide rest, and requires frequent repairs.
To remedy these defects it is one object of this Invention to shape the cutting
end of a drill so as to increase its efficiency and durability; it is a further object of
the invention to hold a drill to be sharpened accurately in the true position without
requiring especial skill on the part of the operator; it is a further object of the
Invention to simplify the construction of drill-sharpening machines, and to obviate
the defects caused by wear; it is a further object of the Invention to provide a
continuous supply of water to the grinding wheel by mechanism that shall be at
once simple and durable; it is a further object of the invention to introduce the
water to the grinding wheel in such a manner that it shall reach the wheel at that
point in its revolution where it operates upon the drill; and to theso ends the
nature of the Invention consists in mechanism for grinding the end surface of each
lip of the drill to a right cone or to a conical surface, the apex of which cone or
conical surface is beyond the point of the drill, while its axis is not parallel to, nor
does it meet the axis of the drill; and it further consists in providing the requisite
clearance back of the cutting edge, by adjusting the angle of the axis of this cone
with reference to the axis of the drill, and its position with reference to the cutting
edge; and it further consists in fixing this angle, and this position, at their best
conditions in the construction of the machine, so that they can not be affected
thereafter by the want of skill in the workman; and it further consists in supplying
water to the grinding wheel by means of a cord or belt pump; and it further
consists in providing a shield which receives the water from the belt-pump and
delivers it upon the wheel only at that point where it operates upon the drill.
The rationale of our invention is as follows :—
Suppose a hollow right cone to be revolving about a horizontal axis, and its
interior surface to be provided with some abrading substance and that the lips of a
drill are inserted into this cone in such manner that the axis of the drill shull
coincide with that of the cone it will be evident that the end of the drill would be
shaped to a right cone but would not have the proper shape for cutting as the centre
of the drill would be a point which would only enter any material to be drilled by
punching or abrasion while the lips back of the edges of the drill would have no

page_text: clearance and hence the drill would merely rub without cutting. Now suppose one
edge of a lip of this drill to be horizontal, move the drill away from the axis of the
abrading cone on a horizontal line, and at the same time lower the drill so that
the cutting edge will be slightly below the centre of the cone, and present the drill
against the abrading cone in this position, the back of the lip will be ground away
first until the cone touches the cutting edge; if the drill is now withdrawn and
turned half round and the other lip presented in the same position it will result
that the end of each lip will be ground to the shape of a right cone and the point
of the drill will be convex like a bow drill for cutting in both directions being
formed by the intersection of the cones forming cach lip; this gives the best
possible shape for the drill point and the clearance will evidently be exactly
adapted to the shape of the bottom of the hole to be produced by the drill. The
distance that the centre of the drill is moved from the apex of the cone depends
upon the thickness of the central part of the drill, and to avoid excessive clearance
on the outside of the drill lip, it is found advantageous in practice, to reduce the
included angle of the hollow cone so that the radius of the cone where it touches
the outside corner of the drill-lip, is but little greater than the radius of the drill
itself for the largest drill the machine is intended to grind; this requires that the
axis of the drill shall not be coincident with, nor parallel to, the axis of the grinding
cone, and it follows that the clearance of the drill-lip will increase slightly from the
outside corner of the cutting edge to the point of the drill.
The shape of the end of the lip of the drill will be part of the surface of a right
cone, the axis of which is coincident with that of the grinding cone, and it is
evident that the same shape of lip would be produced if the grinding cone was
stationary, and the drill was revolved, not about its own axis, but about the axis
of the grinding cone; and it follows that the same shape would be produced by a
grinding wheel, the cutting surface of which is tangent to a sido of this grinding
cone, and arranged to swing about the axis of this cone, the drill in this case being
stationary; and conversely the grinding wheel can be arranged so as to revolve
about a fixed axis with its cutting surface tangent to a side of the right cone to
which the end of the drill lip is to be formed, the drill in this instance being
revolved or swung about the axis of this cone; these methods will all produco
precisely the same form of end to the lip of a drill, and as the method last described
has many mechanical and practical advantages the drawing annexed represents a
machine constructed on this plan.
In the accompanying drawings which form part of this specification, Figure 1
Sheet represents a plan of the drill holding device and grinding-wheel partly in
section. Figure 2 is an end view of the chuck showing the relative position of the
clamping jaws: Figure 3 is an end view of the pump-pulley. Figuros 4 and 5 are
end views of drills of different sizes, showing variation of position with diameter of
drill. Figure 6 represents an elevation of the machine partly in section with the
drill-chuck broken away to show the pump and shield. Figure 7 is an clovation
at right angles with Figure 6. Figure 8 is a section through the deflecting shield
on the lino n' n¹. Figure 9 is a plan of top of post. Figure 10 is a section
through the bearing for drill-chuck showing stops for lever. In all the figures
similar letters refer to similar parts.
A Figure 1 represents a drill held in position for sharpening its lip, a against
the grinding-wheel B; the chuck C has two jaws, D and E sliding freely in grooves
in the face of the chuck C and held in place by the ring G under which they slide
easily, being moved in and out for the purpose of clamping the drill by means of
the hand wheel F, which is provided on its inner face with a scroll thrend, which
fits and engages with a corresponding scroll thread on the jaws D and E; the hand
wheel F is held in position by a flange on the ring G as shown. Projecting from
the back of the chuck C is a rod J which carries a cross-head K provided with a
5 centro L which is concentric with the centre of the chuck. The rod J has a key-
seat extending its entire length in which slides a feather secured in the cross
head K; this keeps the centre L always in the line of the contre of the chuck; the

page_text: cross-head K is clamped to the rod J in any desired position by the screw b. The
centre L carries the end of the drill A the front end being clamped firmly close to
the edge of the lips by the jaws D and E; the position of the drill lips in these
jaws is determined by the stops c and d, against which the lips of the drill are
rotated by hand before clamping; the position of the drill end ways, that is, the
distance that the end of the lip projects from the face of the chuck, is determined
by the stope in the jaw E; these three stops c, d, e, thus determine the exact
position of the lips of the drill with reference to the grinding wheel and the axis
about which they are swung and as the jaws seize the drill close to the lips, and
by a short bearing only, there is no danger of springing any drill to be sharpened.
The chuck C is formed with a shaft or arbor M projecting from it, and which is
fitted so as to turn freely in the bearings fg formed with or secured to the stand O;
the shaft M is formed with a shoulder and provided with a bolt and washer at the
bearing so that it has no end play; the chuck C and with it the drill A can be
rotated about the axis y y of the shaft M by means of the lever h which is formed
with a counterweight for the purpose of balancing the weight of the drill; the
bearing is provided with stops to limit the rotation of the chuck in each
direction. In all the drawings the chuck C is shown in that point of its revolution
where the axis a, a, of the chuck C is horizontal; the axis x is not in the same
plane with the axis y y but lies below it as shown in Figures 2, 4, 5, 6, and 7.
In Figure 1 it will be seen that the axis of rotation of the chuck y y makes an
angle with the axis xx of the chuck itself and also with the cutting face of the
grinding wheel B; if the wheel B be driven and the chuck swung in its bearings f g
it follows that anything held in the chuck C and against the grinding wheel will
be ground to the shape of a right cone the axis of which is the line y y. Figure 11
represents the drill A as having its lip a sharpened entirely to one side of the
axis y y and the cutting edge of this lip, a is represented as just touching the
grinding wheel. If the chuck C be now swung in its bearings by moving
the lever h towards the stop k the end of the lip a of the drill will be ground to
the shape of a right cone the axis of which is the line y y and the apex is the
point where the line y y is cut by the face of the grinding wheel; and as the
cutting edge of the lip a is nearly on the same plane with the axis y y, the axis x x
of the drill and chuck being further below it, it follows that the end of the lip,
will have a regular clearance back of the cutting edge, and by trial a relative posi-
tion will be found for the axes x x and y y, and the stops cde, which will give the
combination of the greatest strength of lip with the most efficient cutting edges;
this position is determined in the construction of the machine and the operator has
only to bring the lips of the drill against the stops before clamping the drill in the
chuck to ensure the constant production of the best shapes. When one lip of the
drill is ground the jaws are released by turning the hand wheel F and the drill is
turned half-way round until the opposite lips come against the stops c and d the
drill being held against the back centre L and clamped in this position; if the chuck
is now swung in its bearings the second lip of the drill will be ground to precisely
the same length as the first lip a and will have precisely the same angle and
clearance and the drill will then produce a hole as nearly as possible to its own
diameter.
It will be seen from Figure 2 that the centre lines of the two jaws D and E
are not in one line but are inclined to each other; this is to compensate for the
difference in thickness of the centres of large and small drills. Figure 4 shows n
large drill held in the jaws with its cutting edges resting against the stops c and d, 5
and it will be seen that the line 'x' passes through the centre of the drill and the
line y y lies just above the cutting edge of the lip a of the drill. Figure 5 repre-
sents a small drill in the same position in the jaws; but the upward movement of
the jaws due to their angle with each other brings the cutting edge into almost the
same position with reference to the line y y as the large drill, while the centre of 5
the small drill is considerably above the line x' x².
On reference to Figure 1 it will be seen that the jaws D and E move in a plane

page_text: at right angles to the axis of the drill so that the stops always remains at the
same distance from the face of the chuck C. From this it results that the point or
centre of the drill will vary in its distance from the chuck according to its diameter
the point of the small drills being much nearer to the chuck and hence nearer to
the axis y y; this brings the point or centre of the drill nearer to the apex of tho
cone in one direction and the angle of the jaws above described brings it closer in
the other direction, hence small drills are sharpened to a curve of smaller radius
than the large drills and all drills will have the same correspondence to the shape
of the end of the hole produced, the curvature in all cases being proportioned to
the diameter of the drill and both these movements are made automatically
without depending upon the skill of the operator. The different position of the
centre of rotation with reference to large and small drills is shown by the small
cross on the line y y in Figures 4 and 5 for a large and a small drill respectively.
The annular grinding-wheel B is fastened to the plate N secured to or formed on
the shaft o which is fitted so as to revolve freely in the bearing m in the vibrating-
frame P which is secured to the shaft n by set-screws, as shown. The shaft n
turns and slides freely in bearings U o' formed on the main post R of the machine
and carries the pulleys p and p' and r; p is secured to the hub of the large
pulley which runs loose on the shaft n and drives the grinding wheel by the
pulley & secured to the shaft o; the bearing o' is provided with a screw thread at
one end in which the screwed hub of the hand-wheel t fits; the shaft n is forced
against the hub of the hand-wheel t by the counter weight u secured to the shaft v
to which is also secured the lever w which presses against the hub or bearing a¹ on
the bottom of the Vibrating-frame P; the hand wheel t moves the shaft n and
with it the frame P carrying the grinding wheel in one direction and the counter-
weight u moves it in the opposite direction and at the same time takes up all lost
motion. The shaft n thus serves as a countershaft to carry the driving pulleys, as
a slide rest to move the grinding wheel against the drill, and as a hinge or pivot
for the frame P, which for the purpose of keeping the cutting face of the grinding.
wheel true and free from ridges, is vibrated back and forth by the bell crank
lever b' which is pivotted to the side of the frame P by the stud c'; the end d' of
the lever b' fits in a groove or recess in the arm e¹ which projects from the main
post R; as the lever b' is raised and lowered by the operator the end d' works
within the groove in the arm e' as a gear tooth works in a rack, and so moves the
vibrating frame P back and forth carrying the grinding wheel past the end of the
lip of the drill, and thus keeping the face of the wheel true. The weight of the
vibrating frame P being almost entirely to one side of the shaft n, keeps the
aru el of the lever always against one side of the groove, and so takes up lost
motion. When the machine is not in use or when the drill is being changed the
lever b' rest against the projection g' on the frame P, and so holds it from swinging
too far back, while, if it is desired to empty the water tank which is formed in the
frame P, the small pin may be withdrawn from the fulcrum pin c', and the lever
slipped sideways until it clears the projection g¹', when the frame can be swung
back and the water emptied. The stand O is pivotted on top of the main post R
by the pin h. The hook-bolt clamps the stand O to the main post R, and holds
it securely in position, a projection ¹ from tho stand O, backs up the hook-bolt j¹
and keeps it from turning and at the same time strikes against the stops ", on
the top plate of the main post R. These stops confine the motion of the stand O
within the angle to which the machine is adapted to grind the end of the drill.
By means of this adjustment of the stand O against the stop the drill may be
sharpened with the two cutting edges forming an angle with each other which
experience has shown to be best adapted for general work, or the stand O may be
moved against the other stop l', and secured by the bolt and the edges of the
drill will then be ground at a much more obtuse angle with each other for the
purpose of drilling thin work such as steel rails, or boiler-work; or the stand O
may be clamped at any position between the stops so as to grind the end of the
lips of the drill to the angle best adapted to the particular work in hand. The

page_text: stand O is provided with a ledge or raised rim all round it to retain the water
which is thrown on the drill and to return it into the vibrating frame P which
forms the water tank from, which the pump draws its supply.
The water is supplied to the drill to be sharpened by means of an endless belt S
preferably perforated or roughened to increase the adhesion of the water; this belt
is driven by the pulley m' which runs freely upon the stud H firmly secured in the
wheel cover Tas shown; the pulley m' is driven by two studs W fastened in tho
front of the plate N; these studs W enter freely into two holes drilled to receive
them in the pulley m¹; this arrangement allows the wheel cover T to be moved up
as the grinding wheel wears, the pins or studs W entering further into the holes in 1
the pulley m¹. The necessary tension on the belt is provided by the lower
pulley q' and frame 1, in which the pulley runs; the frame slides freely in the
pump-case & formed on the front of the wheel cover T, the lower end of the pump-
case being submerged in the water in the tank P; the grinding wheel revolves in
the direction shown by the arrow in Figure 6 and the upper side of the belt carries
the water up through the pump case with such velocity that the water is thrown
off the belt with great force, at the point where the belt begins to curve round the
pump-pulley mi; the upper part of the pump case forms a shield to deflect this
water and guide it so that it is thrown on the grinding wheel through the
opening t¹ shown in Figure 8.
The inside of this shield is so formed that the water thrown from the belt
strikes against the surface of the shield at a very acute angle, so as to change the
direction of the water gradually without checking its velocity, so that the greater
part of the water lifted by the belt is thrown forward and out of the opening t¹,
where it falls on the edge of the drill being sharpened, and against the grinding
wheel. The wheel cover T which is formed in one piece with the pump case and
deflecting shield, covers the outside of the wheel and its front except where the end
of the drill is presented to the grinding wheel; at this point an opening is made
through the front plate, just large enough to receive the largest drill that can be
ground; a part of the front plate is also set back a short distance as shown at u¹
in Figure 1, so as to clear the end of the drill when the grinding wheel is moved
by swinging the tank P as above described. Owing to the high velocity of the
grinding wheel it is very important to prevent the indraft of air to any great
extent as this tends to break up the water, and carry it from the wheel in a fine
spray which would be very objectionable; to prevent this trouble, the wheel
cover Tis made to fit the wheel as closely as possible, and there is a large opening
made in the bottom of the cover at w' in the direction of rotation of the wheel, to
allow the water that enters the case at the point where the drill is ground to
escape into the tank and also to give frco vent to the air that may be drawn in at
any point. A small amount of water will be carried round by the grinding wheel,
and to prevent this water from being thrown off at the back edge of the wheel
cover, the inclined ribs y y' are formed on the inside of the cover just above the
opening w; these ribs serve to break up the adhesion of the water to the wheel,
by forming eddies of air, and their inclination serves to form a slight indraught of
air which prevents the water froin reaching the back of the cover with any
velocity; the lower sides of these ribs act as drains, and a little water runs from
their outer, cuds, falling into the drain 9 which discharges into the tank P. The
cover T is held in place by the studs 2, X; one of these studs 5, is fitted tightly
into the tank P as shown the other fits tightly into the cover and slides freely in
its bearings in the tank; the bearing for the stud 2, in the cover T', is split, and
can be closed so as to hold the stud firmly by the binding screw f¹ so that the
cover can be adjusted as the face of the grinding wheel wears away, so as always
to deliver the water on the edge of the drill, and by releasing the binding-screw,
the cover may be drawn completely off for the purpose of cleaning or repairs.
From the foregoing description it will be seen that the mechanism above
described will produce upon a fly or twist drill, a cutting edge shaped to a right
cone, the apex of which cone is beyond the point of the drill, while its axis is not

page_text: parallel to, nor does it meet the axis of the drill, and the same result will attend
the operation of either of the several nodifications described under the rationale of
this Invention.
It will be observed that throughout the foregoing specification I have shown and
described a combination as producing a drill-lip having the contour of a right cone,
but the advantages of the improvement may be availed of to produce a drill-lip
laving a contour not strictly that of a right cone; thus, if the swinging mechanism
for holding and presenting the drill to the grinding surface should be arranged to
present the drill to the periphery of the grinding-wheel instead of to the side
thereof, the traverse of the grinding-wheel in this case to be parallel to this
grinding surface the axis of the grinding wheel, the line of contact with the drill
at the periphery of this wheel, and the axis about which the chuck swings being
in the same plane, the resultant contour will be that of a right cone; but if the
axis about which the chuck swings should be inclined to this plane, the surface
produced upon the end of the drill-lip would not be that of a right cone because no
part of this surface would be in a right line; but it would still be a conical surface
which would have the same clearance as the right cone I have described: I there-
fore do not limit myself to the production of a drill-lip having the contour of a
right cone but 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: The combination with a revolving grinding wheel of a swinging chuck
which clamps and holds the drill so that the axis of the drill shall not be parallel
to, nor will it meet the axis about which the chuck swings, which axis is at an
angle with the grinding surface, whereby, as the chuck is swung about its axis
substantially as described, and presents the drill to the grinding wheel, the end
surface of the drill-lip is ground conical, and the apex of the conical surface is
beyond the point of the drill, while its axis is not parallel to, nor does it meet the
axis of the drill.
Second-The chuck C substantially as and for the purposes set forth.
:-
Third In a drill-sharpening machine a chuck having two jaws provided with
stops which determine the axial rotation of the drill with reference to the jaws,
substantially as described.
Fourth In a drill-sharpening machine a chuck having two jaws provided with
stops which determine the axial rotation of the drill with reference to the jaws, in
combination with a stop upon one of the jaws, which determines the distance from
the end of the lip of the drill to the face of the chuck substantially as and for the
purposes set forth.
Fifth-In a drill-sharpening machine, a rotating grinding-wheel in combination
with a chuck swinging about the axis of a right cone, to which the end of the lip
of the drill is shaped by the grinding-wheel.
Sixth-In a drill-sharpening machine, a grinding-wheel which rotates a pulloy
of smaller diameter, concentric therewith upon a separate arbor, and a belt pump
driven by this pulley, substantially as and for the purposes set forth.
Seventh-In a drill-sharpening machine the combination of a grinding-wheel
and a belt-pump with a deflecting shield substantially as and for the purposes set
forth.
Eighth-In a drill-sharpening machine an adjustable wheel cover provided
with inclined ribs, and a catch-water drain, substantially as described.
Ninth In a drill-sharpening machine, a grinding-wheel mounted upon a
vibrating frame, secured to a shaft which is moved through its bearings in ono
direction by an adjusting screw, and in the opposite direction by a counterweight,
substantially as and for the purposes set forth.
Tenth In a drill-sharpening machine, a grinding-wheel mounted upon n
vibrating reservoir, having its centre of gravity outside the axis about which it
vibrates so that it will move in one direction by its own weight in combination
with a lever which moves it in the opposite direction, substantially as and for the
purposes set forth,

page_text: Eleventh-A drill in which the end surface of the lip is conical and the apex of
the conical surface is beyond the point of the drill, while its axis is not parallel to,
nor does it meet the axis of the drill.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this twenty sixth day of June One 5
thousand eight hundred and eighty three.