Improved Apparatus for Holding and Giving Motion to Twist Drills whilst they are being Ground or Sharpened.
Year: 1885

page_text: Improved Apparatus for Holding and Giving Motion to Twist
Drills whilst they are being Ground or Sharpened.
I, EDWARD DUNNING BARKER, of 115 Cannon Street, in the City of London,
Engineer do hereby declare the nature of the said invention for "IMPROVED
APPARATUS FOR HOLDING AND GIVING MOTION TO TWIST DRILLS WHILST THEY ARE
BEING GROUND OR SHARPENED " to be as follows:-
It is well known that twist drills require to be ground or sharpened with great
accuracy, and in a peculiar manner in order that they shall drill true holes of
nearly their own diameter, and that their cutting edges shall possess the proper and
requisite clearance to enable them to cut freely. The holding and guiding of the
drill and imparting the necessary rotary motion thereto by hand during the process
of grinding or sharpening in order to fulfil the above requirements necessitates very
great manual dexterity, and is an art not readily attained by ordinary workmen.
Various apparatuses have been devised from time to time for the purpose of enabling
this holding, guiding and motion of the drills to be effected mechanically; but so
far as I am aware all such apparatuses have been very costly to make and liable to
get out of order when in use. These apparatuses have for the most part been
dependent for their action upon accurately fitted compound slide rests, traversing
screws, concentric chucks and other complicated and delicate pieces of mechanism
of that kind. The object of my invention is to produce mechanism for these
purposes which shall be free from all such complicated and delicate parts, and
therefore less costly to make and less liable to get out of order.
The mechanism I employ is of the following character:
On an arm, adapted to fix in a post or other suitable part of the frame carrying
the grinding or sharpening wheel, or at some other point sufficiently near to the
said grinding or sharpening wheel, I mount a bar fulcrumed at one end to the said
arm. This bar is fitted near its front end at a point nearly over its fulcrum, with
a V groove in which the drill to be ground or sharpened can be loosely secured so
as to be free to turn therein. The tail end of the aforesaid bar is made of prismatic
or other suitable section such that a kind of headstock can be adjusted and
clamped longitudinally thereon” in various positions to suit the length of the drill
CD 71

page_text: to be ground or sharpened, and laterally or vertically thereon, to a limited extent,
to suit the diameter of the said drill. This headstock carries a hollow shaft the
axis of which coincides with that of the drill to be ground, when the latter is in
position in its V groove. This hollow shaft carries at one end an arm furnished
with a hinged spring latch or catch which takes into the notches of a kind of
The
division plate and driver combined clamped on to the shank of the drill.
other end of the hollow shaft carries a toothed sector by which it can be partially
rotated backwards and forwards by means to be hereinafter described. Through
the centre of the hollow shaft passes a reversible plug or spindle having a male
centre at one end and a female centre at the other, and which can be adjusted
forward or backward by means of a tail or feed screw. One end of this reversible
plug or spindle (viz, the male end in the case of a drill having a sunk centre at its
shank end, and vice versa) is adapted to receive and support the shank end of the
drill to be ground, while the rear end of the said reversible plug or spindle is acted
on by the aforesaid tail screw. If preferred the tail or feed screw may be extended
through the hollow shaft and its end be adapted to receive and support the shank
end of the drill the aforesaid separate plug or spindle being in that case
dispensed with. The headstock also carries a second shaft, on the outer end of
which is secured a second toothed sector which gears with that on the aforesaid
hollow shaft. On the inner end of the second shaft is a crank carrying a long arm
or crank pin which takes between the jaws of a fork turning on a fulcruin in the
first above mentioned arm. The second shaft, which, for the sake of distinction,
may be called the crank shaft, can be turned partly round in either direction by
means of a handle secured thereto or to the sector on it, or the handle may if
preferred be secured to the first above mentioned sector, or to the hollow shaft.
The action of the apparatus is as follows:-
The first abovementioned arm (which may be called the fixed arm and which
carries the whole apparatus) being secured in the post or other point of attachment
in proper position with relation to the grinding or sharpening wheel, the drill
to be ground or sharpened is placed in its V groove and clamped therein by a
spring or other adjustable clamp which leaves it free to revolve in the said V groove.
The shank end of the drill is placed in the end of the reversible plug or spindle or
of the tail or feed screw as the case may be, the headstock being adjusted and
clamped on the bar to the proper positions longitudinally and vertically or laterally
so that the hollow shaft is truly in line or nearly so with the axis of the drill. The
division plate and driver which has two notches diametrically opposite to each
other, is clamped on the shank of the drill, and the spring latch on the arm of the
hollow shaft is placed in one of the said notches. The drill is then advanced
towards the grinding or sharpening wheel to the required extent by means of the
tail or feed screw, and the crank shaft is caused to turn backwards and forwards, to
an extent limited by suitable fixed stops, by the action of the aforesaid handle.
The effect of this partial rotation backwards and forwards of the crank shaft is
twofold. In, the first place, the crank with its long arm or crank pin causes the
beforementioned bar with its V groove and headstock, and the drill held by them,
to oscillate round the fulcrum of the said bar on the fixed arm, the point of the
drill being more or less nearly over the said fulcrum. In the second place, the
toothed sector on the crank shaft gearing with the sector on the hollow shaft causes
the partial rotation backwards and forwards of the latter; and this by its arm and
spring latch causes the division plate and the drill to rotate partially in the same
way. By these means a compound vibrating and partial rotary motion of the drill
is effected, such that as the grinding or sharpening wheel rotates in front of the
drill, while these motions of the drill are produced it grinds one cutting edge of the
drill to the required shape and with the required clearance. When one cutting
edge is ground the drill is retired by means of the tail or feed screw, or otherwise,
the spring catch is released from its notch in the division plate, and the latter is
turned round half a revololution so as to bring the other notch thereof opposite
the spring catch which is then placed therein and the other cutting edge of the drill

page_text: is thereby brought into position to he acted on by the grinding wheel when the
beforementioned compound movements of the drill are repeated.
Suitable stops acting in relation to the tail or feed screw and hollow mandril are
provided in order to ensure an equal grinding or sharpening of each of the two
faces of the cutting end of the drill.
The above described apparatus is very cheaply constructed because there is no
accurate fitting required in any of the parts, and the material, of which compara-
tively little is required, may be of an inexpensive character.
E. D. BARKER
Per. W. H. Beck, Agent.
Improved Apparatus for Holding and Giving Motion to Twist
Drills whilst they are being Ground or Sharpened.
I, EDWARD DUNNING BARKER, of 115 Cannon Street, in the City of London,
Engineer, do hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying sheets of Drawings
and to the letters and figures marked thereon:-
It is well known that twist drills require to be ground or sharpened with great
accuracy, and in a peculiar manner in order that they shall drill true holes of nearly
their own diameter, and that their cutting edges shall possess the proper and
requisite clearance to enable them to cut freely. The holding and guiding of the
drill and imparting the necessary rotary motion thereto by hand, during the process
of grinding or sharpening in order to fulfil the above requirements, necessitates very
great manual dexterity, and is an art not readily attained by ordinary workmen.
Various apparatuses have been devised from time to time for the purpose of enabling
this holding, guiding, and motion of the drill, to be effected mechanically, but, so
far as I am aware, all such apparatuses have been very costly to make, and liable
to get out of order when in use. These apparatuses have, for the most part, been
dependent for their action upon accurately fitted compound slide rests, traversing
screws, concentric chucks, and other compplicated and delicate pieces of mechanism
of that kind. The object of my invention is to produce mechanism for these
purposes which shall be free from all such complicated and delicate parts, and
therefore less costly to make, and less liable to get out of order.
The mechanism I employ is of the character illustrated in the accompanying
sheets of Drawings in which Figure 1 is a plan, Figure 2 a front elevation, and
Figure 3 an end view, of the apparatus applied to an ordinary grinding machine.

page_text: On an arm A, fixed to the frame or headstock A¹ carrying the grinding <r
sharpening wheel A², or at some other point sufficiently near to the said grinding
or sharpening wheel, I mount a bar B fulcrumed by a conical pin B' taking into a
conical hole in the arm A. The pin B¹ and hole into which it fits may be cylindrical,
but I prefer them to be conical, as greater steadiness of motion and rigidity are
thereby attained. The bar B is fitted with a V grooved piece C the stem of which
takes into a hole in the said bar B and is adjustabe vertically therein to suit drills
of various diameters. The drill D, to be ground or sharpened, is laid in the V groove
and loosely secured therein by the pressure upon it of the tearing piece E which is
held down by the weight E' hung to it, or by a spring, if preferred. The pressure
upon the drill must not be sufficient to prevent it from turning freely on its axis in
the V groove, and the length of the said V groove must be sufficient to secure a
continuous bearing for the spiral part of the drill body. The tail part of the bar B
is made of prismatic or other suitable section such, that a kind of headstock F can
be moved longitudinally and clamped thereon by the set screw F1, in various positions
to suit the length of the drill. to be ground or sharpened. This headstock may be
arranged so as to be adjustable vertically on the bar to a limited extent to suit the
diameter of the drill, but in most cases this vertical adjustment is not necessary:
The headstock F caries a bracket G formed, if preferred, in one piece with the
headstock F; it carries a hollow shaft H, the axis of which coincides with that of
the drill D to be ground, when the latter is in position in its V groove. This hollow
shaft H carries at one end an arm H* furnished with a spring latch, catch, or bolt I
which takes into the notches of a kind of division plate and driver combined J
clamped on to the shank of the drill D (see also figure 4). The other end of the
hollow shalt H carries a toothed sector, or, if preferred, an arm K as shown by
which its partial rotary motion, backwards and forwards, can be transmitted to the
shaft L, or vice versa, by means to be hereinafter described. Through the centre of
the hollow shaft passes a plug or spindle H' provided with a male conical centre at
one end adapted to take into the sunk centre hole usually found in the shank end
of the drill. The spindle H¹ may be made with a female conical centre to receive
the shank ends of small drills which may not have the usual sunk centre hole, or
the spindle may be made reversible, that is, with a male conical centre at one end,
and a female conical centre at the other. This spindle H¹ can be fed forward
towards the grinding wheel by means of the tail or feed screw H' acting on the
rear end of the said spindle. If preferred, the tail or feed screw H² may be extended
through the hollow shaft H and its end be adapted to receive and support the shank
end of the drill, the aforesaid separate plug or spindle H¹ being, in that case,
dispensed with. The headstock Falso carries a second shaft L on the which is a
second toothed sector which gears with that on the hollow shaft H, or, if preferred,
a second arm M on a boss M₁ capable of sliding on the shaft L but of being fixed
thereto by a screw or key may be employed, the said arm M being connected with
the arm K on the hollow shaft H by the link N. On the end of the shaft L is a
crank or arm O the lower end of which is screwed into a nut P which is free to
turn between the jaws of a fork Q screwed on, or otherwise connected with, and
so as to turn freely on, a rod or arm R screwed in a nut R¹ turning in the jaws of
a fork R³ swivelling on the headstock A¹ of the grinding machine. The shaft L
can be turned partly round in either direction by means of a handle secured thereto
or to the toothed sector on it, when such is employed, or the handle may, if preferred,
be secured to the toothed sector on the hollow shaft, when such sector is employed,
or to the hollow shaft itself, as shown at S.
The action of the apparatus is as follows:-
The arm A (which may be called the fixed arm, and which carries the whole
apparatus) being secured in proper position with relation to the grinding or
sharpening wheel A², the drill D to be ground or sharpened is placed in the
V groove of the piece C and clamped therein by the bearing piece E, which leaves
it free to revolve in the said V groove. The shank end of the drill D is placed on
the male conical end of the plug or spindle H', or of the tail or feed screw H³ when

page_text: the same is extended through the hollow shaft H as above described, or in the
female conical end of the plug or spindle H¹, or of the extended tail or feed screw.
The headstock F is adjusted and clamped on the bar B to the proper position longi-
tudinally, so that the point of the drill D is brought sufficiently near the grinding
wheel A. The division plate and driver J, which has two notches J' diametrically
opposite to each other, is clamped on the shank of the drill, and the spring bolt I,
in the arm H¹ of the hollow shaft H, is placed in one of the said notches. This
bolt I slides end wise in the boss H³ of the arm H' and can be turned round
therein by the handle I¹, the spring 12 tending always to draw the bolt I
towards the left in Figures 1 and 2. The bolt I is furnished with a T head I³
the shoulders of which bear against the division plate J as shown in Figures 1
and 2, the spring 13 acting by that means to hold the drill back against the
end of the spindle H'. When the bolt I is turned one quarter round by the
handle 11, the spring 12 draws the said bolt through, and clear, of the notch J¹,
setting the division plate J free to be turned round with the drill one half of
a revolution, so as to bring the other notch opposite the bolt I which can then
be passed through it and turned one quarter back again so as to place the
head 13 across the notch J₁ as before. The drill D is then advanced towards the
grinding wheel A² to the required extent by means of the tail or feed screw H²,
and the shaft L is caused to turn back wards and forwards, to an extent limited
by suitable fixed stops, by the action of a handle such as that shown in dotted
lines at T in Figure 2 for example. The effect of this partial rotation backwards
and forwards of the shaft L is two-fold. In the first place, the lower end of
the crank or arm being prevented by its connection with the rod R from
following the rotation of the shaft L while the arm B is stationary, constrains the
latter, in order to allow of the partial rotation of the shafts L and H, to oscillate
with its V grooved piece C, headstock F, and the drill D, held by them, roundl
the fulcrum B₁ of the said bar B on the fixed arm A so as to traverse the one
cutting edge of the drill across the face of the grinding wheel. In the second
place, the toothed sector on the shaft L gearing with the toothed sector on the
hollow shaft H, when such sectors are employed, or the arm M, link N and arm K,
as in the arrangements shown in the Drawings, cause the division plate J and the
drill D to rotate partially in the same way. Instead of the partial rotary motions,
of the shaft L and hollow shaft H, being produced by the operation of a handle T
on the shaft L, the same effects may preferably be produced by the operation of a
handle S fixed on the hollow shaft H.
By either of these means a compound motion of the drill is produced composed
of a partial rotary motion round its axis and of an oscillating motion round the
fulcrum B¹ which latter motion has the effect of traversing the end of the drill
across the face of the grinding wheel and at the same time of causing the drill to
move endwise towards the grinding wheel as the said drill is rotated on its axis in
one direction, and to move it endwise away from the wheel as it is turned in the
opposite direction, the whole effect of the compound motion being, that as the
grinding or sharpening wheel A* rotates in front of the drill, while these motions
of the drill are produced, it grinds one cutting edge of the drill to the required
shape, produces the requisite chisel form of the point, and gives the required
clearance at the back of the cutting edge. When one cutting edge is ground, the
drill is retired by means of the tail or feed screw H2, (the spring 1* co-operating to
that effect) the spring bolt I is turned a quarter round by its handle and is thereby
released from the notch J¹ in the division plate or driver J, the latter, with the
drill D, is then turned round by hand half a revolution so as to bring the other
notch of such division plate or driver opposite the spring bolt I which is then
pushed into the said notch and turned back a quarter of a revolution so as to lock
it therein, and the other cutting edge of the drill is thereby brought into position
to be acted on by the grinding wheel A3, when the drill is again fed forward by the
feed screw H, and the beforementioned compound movements of the drill are
repeated. The feed screw H* is turned by the milled head U, and a washer or

page_text: collar V is placed on the screw H2, being secured thereon in any position circum-
ferentially by means of a thumb screw W. When one edge of the drill is ground,
the thumb screw W is brought into contact with the stop X on the hollow shaft H,
and the washer or collar V is secured on the screw H2 by the said thumb screw, so
that when the other edge of the drill is ground, the forward rotation of the feed
screw is stopped when the thumb screw W again comes against the stop X, whereby
equal grinding or sharpening of the two cutting edges of the drill is ensured.
Instead of the crank or arm O on the shaft L being jointed to a rod R as above
described, for the purpose of effecting the oscillation of the bar B round its
fulcrum B, the lower end of the said arın O may be forked and arranged to take
over, or be otherwise suitably connected to, the end of a fixed arm Y extending
from the arm A, which arm A is adjustable with reference to the headstock A¹, as
shown in Figure 2, in order to allow the apparatus to be moved towards the spindle
of the grinding wheel A' as the said wheel wears.
The above described apparatus is very cheaply constructed because there is little
or no accurate fitting required in any of the parts, and the material, of which
comparatively little is required, may be of an inexpensive character.
I am aware that an apparatus has already been devised and used in which the
drill has been caused to rotate partially on its axis, and at the same time to move
endwise and to oscillate backwards and forwards horizontally. round a fulcrum
placed almost immediately beneath the point of the drill, but in that apparatus the
endlong movement of the drill, necessary to produce the required chisel form of
the point thereof, is effected by a pin traversing a spiral slot in a hollow sleeve or
shaft, and the necessary traversing movement of the drill across the face of the
grinding wheel is effected by traversing the wheel by a special appliance in front
of the drill. In my improved apparatus, the drill has similar movements imparted
to it, but by placing the fulcrum on which the apparatus oscillates horizontally in
the position shown in the Drawings, that is to say, to one side of the axis of the
drill and somewhat behind the point thereof, I effect the required endlong motion
of the drill without the use of a spiral slot, and at the same time effect the necessary
traverse of the drill across the face of the grinding wheel without traversing the
latter.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
First. The improved apparatus for holding and giving motion to twist drills,
whilst they are being ground or sharpened, consisting of a bar furnished with
devices for holding and rotating the twist drill, and for imparting to the said bar
and to the drill mounted thereon, an oscillating motion round a fulcrum, which
fulcrum is so placed that the oscillation, round such fulcrum, of the said bar with
the drill mounted thereon, moves the drill endwise and traverses it across the face
of the grinding wheel, as hereinbefore described, and illustrated in the Drawings
hereto annexed.
Second. The devices for effecting the rotary movements of the drill on its axis,
and the oscillating motion of the apparatus round its fulcrum, consisting of the
shafts Hand L, operated by the handles T or S, and geared, or otherwise connected,
together, so as to transmit motion from one to the other; the shaft L having at
one end a crank or arm O the end of which is prevented by its connection with a
fixed point from following the oscillating notion of the apparatus round its fulcrum,
the whole arranged, combined, and operating, as herein before described, and
illustrated in the Drawings hereto annexed.
Third. The devices for holding the drill and transmitting rotary motion thereto,
consisting of the hollow shaft H, the plug or spindle H₁ with male or female
conical end, or in the alternative, the feed screw H² extended through the hollow
shaft and provided with male or female conical end, the spring latch, catch, or
bolt I carried by the hollow shaft, and the combined division plate and driver J

page_text: clamped on the drill shank, the whole arranged, combined, and operating together
substantially as herein before described, and illustrated in the Drawings hereto
annexed.
Fourth. The devices for feeding the drill forward to the grinding wheel, and
for securing the equal grinding of both cutting edges of the drill, consisting of the
feed screw H, the washer or collar V, the thumb screw W, and the stop X on the
hollow shaft H, the whole arrange, combined, and operating substantially as
hereinbefore, described, and illustrated in the Drawings hereto annexed.
Dated this 8th day of January 1886.
E. D. BARKER.
Per W. H. Beck, Agent.