Improvements in Mechanism or Arrangements for Grinding or Sharpening Twist Drills.
Year: 1889

page_text: Date of Application, 25th June, 1889
Complete Specification Left, 5th Mar., 1890-Accepted 26th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Mechanism or Arrangements for Grinding or
Sharpening Twist Drills.
1, GRAY DENISON EDMESTON, of 29 Jolinson Street, Cheetham, in the City of
Manchester, in the County of Lancaster, Engineer, do hereby declare the nature of
the said invention to be as follows:-
My invention relates to mechanism or apparatus for holding and guiding tools
known as twist drills, while their cutting edges are being ground or sharpened,
and it is more especially designed for use in connection with an ordinary grinding
stone or tool grinder, and is arranged so as to be clamped or secured to and
removed from the tool rest of such machines, or the ordinary tool rest may have an
addition made to it, or it may be modified, to receive and hold the said twist drill
holding and guiding apparatus, which consists of a clamp part that will pass over
the ordinary tool rest and can be secured thereto, on one side of and clear of the
grinding stone, by a pinching screw. On one side of this clamp there is a vertical
flange with a hole passing through it to receive a horizontal screwed fulcrum pin,
and also a segmental slot for receiving a locking screw by means of which I attach to
it a part that I will term the "front table," which is intended to receive the cutting end
of the drill. This "front table" lies upon the top of the tool rest and by means of
the horizontal fulcrum pin and locking screw can be secured at any required angle
be
above or below the horizontal position so that the cutting edge to be ground may
presented to the cylindrical face of the grinding stone or wheel at such an angle as
will give the required "back rake" to the said cutting edge.
The "front table" has a vertical fence rising from it, diverging laterally, and
which forms a rest for the side of the drill and is at such an angle that when the drill
is resting in the angle formed by the table and its fence, the cutting side to be ground,
will be parallel to the cylindrical face of the grinding stone or wheel.
"
Projecting outwards from the "front table" there is a screwed and grooved arm
or stem for receiving an arm bracket" which slides freely upon it, to and fro, to
suit the varying lengths of the drills and it has a key groove fitted with a key and
a pinching screw for retaining it in position, and also a propelling nut for advancing
it towards the face of the grinding stone. This "arm bracket" carries a part which
I will call the "back table" which is intended to support the shank end of the drill
and also an adjustable "abutment piece" which is screwed to it by a winged nut,
the "arm bracket," "back table" and "abutment piece" together form an irregular
four sided opening in which the rear, or shank end of the drill is rotated and guided
during the operation of grinding.
For giving motion to the drill I use a "hand socket" or "chuck" which is bored
with a taper hole for receiving drills with tapering shanks, or with a parallel hole for
is provided
receiving drills with parallel shanks, in the latter case the "hand socket'
with a pinching screw for fixing it to the drill, while in the former case a slight blow
on the end of the drill or the socket" is sufficient to secure it, and a thumb screw
may be provided at the rear end for forcing the drill out of the "socket." The
front end of the socket is formed with a collar having two projecting studs upon
its face, placed on diametrically opposite sides of its axis. The apparatus is used as
follows. The "arm bracket" with its "back table" being adjusted approximately
to the length of the drill the drill to be ground is placed resting upon the two
tables, and against the vertical fence, with one cutting edge turned upwards and
level, in which position it will be parallel to the cylindrical face of the grinding stone
or wheel, the "hand socket" is then passed on to the shank of the drill, with one of
its projection studs resting upon the face of the "back table" the drill is secured in

page_text: this position to the "hand socket" either by a slight blow, or by the pinching screw,
according to the form of the shank as before explained.
:
"
The abutment piece" is adjustable to come against the projecting stud nearest to
it and secured by the winged nut, the face of the collar of the "hand socket" is
pressed against the edge of the "back table" and this limits the distance to which
the drill can be pushed towards the grinding stone or wheel, the propelling nut on the
screwed arm is rotated to advance the "arm bracket until the cutting edge of the
drill is brought against the grinding stone or wheel, and this will grind a facet on
the drill with the requisite clearance or "back rake," then by rotating the "hand
socket" keeping its collar bearing against the edge of the back table" and its
projecting stud bearing against the "abutment piece" the drill can be rotated
through an angle of 60 or 70 degrees and its shank end moved laterally on the "back
table from right to left, the cutting end of the drill being at the same time held
with its side against the vertical fence of the "front table" the "back rake" will be
continued beyond the first facet and the chisel point of the drill will be moved clear
of the grinding stone or wheel.
"
When one cutting edge has been sharpened and backed off as explained it is only
necessary to rotate the "hand socket" half a turn, to grind the opposite cutting edge
in like manner, and to an equal and uniform extent.
Dated this Twenty-fourth day of June 1889.
PETER J. LIVSEY,
Agent.
COMPLETE
SPECIFICATION.
Improvements in Mechanism or Arrangements for Grinding or
Sharpening Twist Drills.
I, GRAY DENISON EDMESTON, of 29 Johnson Street, Cheetham, in the City of
Manchester, in the County of Lancaster, Engineer, 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:-
My invention relates to mechanism or apparatus for holding and guiding tools
known as twist drills, while their cutting edges are being ground or sharpened, and
it is more especially designed for use in connection with an ordinary grinding stone
or tool grinder, and is arranged so as to be clamped or secured to and removed from
the tool rest of such machines, or the ordinary tool rest may have an addition made
to it, or it may be modified to receive and hold the said twist drill holding and
guiding apparatus, which consists of a clamp part that will pass over the ordinary
tool rest and can be secured thereto, on one side of and clear of the grinding stone,
by a pinching screw. On one side of this clamp there is a vertical flange with a
hole passing through it to receive a horizontal screwed fulcrum pin, and also a
segmental slot for receiving a locking screw by means of which I attach to it a part
that I will term the "front table" which is intended to receive the cutting end of the drill.
This "front table" lies upon the top of the tool rest, and by means of the horizontal
fulcrum pin and locking screw, can be secured at any required angle 'above or below
the horizontal position so that the cutting edge to be ground may be presented to
the cylindrical face of the grinding stone or wheel at such an angle as will give the
required back rake" to the said cutting edge.
"
The "front table has a vertical fence rising from it, diverging laterally, and
which forms a rest for the side of the drill and is at such an angle that when the
drill is resting in the angle formed by the table and its fence, the cutting side to be
ground will be parallel to the cylindrical face of the grinding stone or wheel.
Projecting outwards from the "front table" there is a screwed and grooved
arm or stem for receiving an "arm bracket" which slides freely upon it, to and fro,
to suit the varying lengths of the drills and it has a key groove fitted with a key
and a pinching screw for retaining it in position, and also a propelling nut for

page_text: advancing it towards the face of the grinding stone. This " arm bracket" carries a
part which I will call the "back table" which is intended to support the shank end
of the drill and also an adjustable "abutment piece" which is screwed to it by a
winged nut, the arm bracket," "back table" and "abutment piece" together form
an irregular four sided opening in which the rear or shank end of the drill is rotated
and guided during the operation of grinding.
"
For giving motion to the drill I use a "hand socket" or "chuck" which is bored
with a taper hole for receiving drills with tapering shanks, or with a parallel hole for
receiving drills with parallel shanks, in the latter case the "hand socket" is provided
with a pinching screw for fixing it to the drill, while in the former case a slight
blow on the end of the drill or the "socket" is sufficient to secure it, and a thumb
screw may be provided at the rear end for forcing the drill out of the "socket."
The front end of the socket is formed with a collar having two projecting studs upon
its face, placed on diametrically opposite sides of its axis.
The apparatus is used as follows. The "arm bracket" with its "back table" being
adjusted approximately to the length of the drill, the drill to be ground is placed
resting upon the two tables and against the vertical fence, with one cutting edge
turned upwards and level, in which position it will be parallel to the cylindrical face
of the grinding stone or wheel, the "hand socket" is then passed on to the shank
of the drill, with one of its projecting studs resting upon the face of the "back
table" the drill is secured in this position to the "hand socket" either by a slight
blow, or by the pinching screw, according to the form of the shank as before
explained.
The "abutment piece" is adjustable to come against the projecting stud nearest
to it and secured by the winged nut, the face of the collar of the "hand socket" is
pressed against the edge of the "back table" and this limits the distance to which
the drill can be pushed towards the grinding stone or wheel, the propelling nut on the
screwed arm is rotated to advance the "arm bracket" until the cutting edge of the
drill is brought against the grinding stone or wheel, and this will grind a facet on
the drill with the requisite clearance or "back rake" then by rotating the "hand
socket" keeping its collar bearing against the edge of the "back table" and its
projecting stud bearing (to the left hand) against the "abutment piece," the drill can
be rotated through an angle of 60 or 70 degrees, and its shank end moved laterally
on the "back table" from right to left, the cutting end of the drill being at the
same time held with its side against the vertical fence (to the right hand) of the
"front table" the "back rake" will be continued beyond the first facet and
the chisel point of the drill will be moved clear of the grinding stone or wheel.
When one cutting edge has been sharpened and backed off as explained it is
only necessary to rotate the "hand socket" half a turn, to grind the opposite cutting
edge in like manner, and to an equal and uniform extent.
It is important for the formation of a true chisel point to the drill, that during
the first part of its rotation, it should be slightly withdrawn in its longitudinal
direction, so that its lower edge will clear the grinding surfaces, and to effect this
the flat portion of the front edge of the "back table" is continued for a short
distance to the left of the axis of the drill, and from that point it is formed convex,
to a radius about equal to the length of the shortest drill to be ground,
The position of the termination of this flat portion requires also to be varied
according to the diameter of the drill; the most suitable position being found to be
at about two thirds of the radius of the drill's diameter to the left of the axis.
This is effected by forming two projections or corner pieces upon the flange of
the "hand socket" which bear against the "abutment piece" when the cutting edge
is being ground; the "abutment piece" and "back table being adjusted to these
projections or corner pieces, and thus the position of the abutment piece will vary
according to the elevation of the axis of the "socket" above the " table" due to
the difference in the diameter of the drills being operated upon.
"
Two alternative forms of the "hand socket" and "adjustable abutment piece
may also be used; in both of which the "abutment piece" is placed to the right

page_text: hand of the axis of the drill; instead of to the left hand as above. In the first of
these, the flange of the "hand socket" is formed with two parallel flat edges, equi-
distant from the axis, each of which is held against a sloping abutment piece, on
the right hand of the axis whilst the corresponding cutting edge is being ground,
and the two studs upon the face of the flange are used to produce the lateral
movement of, the drill from right to left during the backing off process, by rotating
against a secondary adjustable curved abutment, and also limiting the amount of
rotation of the drill upon its axis during the operation by coming to rest upon the
upper surface of the "back table."
In the second alternative form, the profile of the flange of the "hand socket" is
rhomboidal in outline, with its obtuse angles rounded off; these obtuse angles being
of such amplitude as to correspond to the angle of rotation required to be given to
the drill, and the difference between the shorter and longer diameters of the Hange is
sufficient to produce the required lateral movement during the process of "backing
off" when rotated against an adjustable "sloping abutment piece.'"
The inclination of the "sloping abutment piece" in both of these alternate forms
provides for the variation in the position of the axis of the drill in relation to the
Hat upon the edge of the "back table" according to the varying diameters of the
drills to be operated upon.
In the accompanying drawings which form part of this specification the figures
upon sheet 1 represent the details of the apparatus on a reduced scale. Those on
sheet 2 represent enlarged details of portions of the same, and those on sheet 3
represent the two alternative forms of the hand socket and adjustable abutment piece.
As far as possible the same letters of reference indicate the same parts in all the
drawings.
In sheet 1, fig. 1 is a plan of the apparatus, fig. 2 is an end view of the arm
bracket with its adjustable abutment; fig. 3 is an elevation of the front table in
section through the line A-B fig. 1, fig. 4 is a side elevation of the clamp, fixed to
the tool rest, taken in section on the line C-D and fig. 5 is a front elevation of the
clamp.
In sheet 2, fig. 6 is an enlarged plan taken in section through the line E-F on
fig. 2, showing the position of the drill and hand socket during the grinding of the
cutting edges, and also their position when finishing the backing off process.
Fig. 7 is an enlarged view of fig. 2.
a, figs. 1 and 6 represents a drill in position during the grinding of its cutting
edges with the grindstone partly shown by b, the axis of which is at 61, fig. 4; c, is
the ordinary tool rest of the grindstone, d, the clamp attached to the rest c, secured to
the ordinary trough c¹, by the pinching screw d'; e, is the front table bracket, attached
to the flange d², of the clamp d, by the two screws d³, and d, and allowing of
radial adjustment around the axis d³, by means of the segmental slot d, fig. 4. e¹, is
the horizontal portion of the table for receiving the cutting end of the drill a, and e²,
is the vertical side fence rising from the table e¹, (see fig. 3) and diverging laterally
from the face of the grindstone b, and against which side fence the cutting end of the
drill is held during grinding.
es, is the screwed arm of the front table bracket, for receiving and supporting
the arm bracket f, the arm e³, has a key-groove et, (see figs. 7, 2 and 3) on one
side, and the arm bracket f, is bored to slide freely to and fro, upon the outside of
the threaded portion of the arm e³, and is prevented from rotating upon it by
being provided with a corresponding key-groove and fitted with a feather key, and
also with a thumb screw f¹, (see figs. 1 and 2) by which it may be tightened at any
point upon the arm e³, the screwed part of the arm e, is also provided with a
capstan nut g, which propels the arm bracket f, in a direction towards the grinding
surface of the grindstone b.
h, is the adjustable abutment piece attached to the outer vertical face of the arm
bracket f, and is secured to it by the bolt and wing nut h³, this abutment piece h, is also
connected to the part called 'the back table 7, which rests, and slides upon the
projecting arm of the arm bracket f, and has its upper surface in the same horizontal

page_text: plane as the portion e', of the front table, and is for the support of the rear portion of
the barrel of the drill.
i, is the hand socket, bored to fit the shank end a', of the drill a.
One end of the socket i, is formed with a collar or flange, the profile of which is
shown in dotted lines 2, in fig. 7.
,, are the two projecting studs placed on diametrically opposite sides, and
equidistant from the axis of the socket i.
(see fig. 1) is a thumb screw fitted to the opposite end of the socket i, and is
used for forcing the drill out of the socket after grinding.
The standard form of shanks of twist drills, is conical as shown at a¹, but the
socket i, may be bored cylindrically, to fit drills with cylindrical shanks, and in that
case would be provided with a side pinching screw for fixing it upon the shanks.
The form of the front edge of the back table 2, is most clearly shown in
figs. 6 and 7, the flat portion before referred to extends from h³, to 4, fig. 6, from
which latter point it is slightly rounded off to the line h, the strong dotted lines
show the position of the drill a, and hand socket i, during the grinding of the cutting
edges, and the faint dotted lines the position of the same at the completion of the
backing off process; the front edge of the back table has also a lower projection *,
which acts as a stop for the studs 3, and, limiting the angle of rotation of the
socket i, during the backing off process. The profile of the flange of the socket i,
and the projections upon it for regulating the adjustment of the abutment h, are
shown at i, and 17.
The front table e, is formed with a prolongation e³, and additional vertical side
fence e, intended to be used in grinding drills when they are worn too short to be
ground against the fence e².
When this table e, is used, the abutment piece h, is moved to the left hand, so that
the bolt with wing nut h¹, passes through the hole provided for it at 7.
The figures on sheet 3 represent the two alternate forms of hand socket and
abutment piece.
Figs. 8, 9; 10 and 11 illustrate the first of the alternate forms hereinhefore
referred to.
Fig. 8 being an end elevation, and fig. 9 a plan of the arm bracket f, with its
modifications.
Fig. 10 is a plan of the hand socket i, and fig. 11 a front elevation of the
flange i².
h, is the adjustable abutment piece, with its back table h³, secured as before to
the face of the arm bracket f, by the bolt and wing nut ; to the outer face of h,
is fixed a secondary abutment piece 4, adjustable diagonally in an angle of about
60 degrees and secured in position by the thumb screw 8; the upper portion of the
secondary abutment piece 10, has a projecting finger, which limits the downward
diagonal adjustment, by being brought to rest upon one of the projecting studs ³,
or of the flange, of the hand socket i, when it is placed in its position for
grinding the cutting edge of the drill as shown in fig. 8, in which the strong
dotted lines represent the position of the flange, during the grinding of the cutting
edge, and the faint dotted lines its position at the completion of the backing off
process.
The profile of the flange ², of the hand socket i, is also shown in fig. 11,
8, and, are the two parallel flat edges equidistant from the axis of the socket,
and, are the two projecting studs herein before referred to; in all other respects
the hand socket i, is the same as shown in fig. 1 sheet 1 and fig. 6 sheet 2.
A graduated scale ", upon the upper edge of the abutment piece h, and an index
point, is used to facilitate the setting of the abutment piece h, according to the
diameter of the drill to be ground.
In using this form of the apparatus the procedure is the same as herein before
described, and which refers more particularly to the form illustrated on sheets 1
and 2, except that the hand socket i, is passed on and fixed to the stem or shank of the
drill, so that one of its parallel flat edges, may take a bearing to the right hand, against

page_text: the secondary abutment 10. In this position the stud *, will be above the table h²
the secondary abutment piece 10, is then set so that the finger h, touches the
stud, and when one cutting edge has been ground, the opposite edge is ground
with the flat edge, against the secondary abutment.
In backing off, the socket i, is rotated into the position shown by the faint dotted
lines (fig. 8) with the projecting stud or studs 3, and i*, bearing to the right against
the secondary abutment ho, until the studs come to rest upon the back
table 2, and this limits the amount of rotation during the backing off process.
Figs. 12, 13, 14 and 15 illustrate the second alternative form herein before referred
to; in this form the abutment piece h, (figs. 12 and 13) is the same as h, in
figs. 8 and 9, except that the secondary abutment 1, is dispensed with; a sloping
abutment flange h¹, taking the place of it, and the flange, of the hand socket
(figs. 14 and 15) is formed approximately rhomboidal in outline, without any pro-
jecting studs, the two parallel sides 10, 11, serving to adjust the drill during the grinding
of the cutting edges, and the two parallel sides 12, 3, limiting the angle of rotation
during the backing off process, the former position being shown by the strong dotted
lines, and the latter position by the faint dotted lines (fig. 12).
In using this form of the apparatus the procedure is the same as described for
the form illustrated in figs. 8 to 11, except that the secondary abutment piece being
absent, no secondary adjustment is necessary.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
1. The front table bracket with its projecting screwed arm, and side fence upon
and against which the cutting end of twist drills may be held and rotated during the
grinding and backing off of their cutting edges substantially in the manner herein-
Before described and illustrated by the drawings.
2. The arm bracket with its adjustable abutment piece and back table, for sup-
porting and directing and controlling the motion of the rear portion of the barrel
of the drill, and sliding to and fro and adjustable upon the screwed arm of the
front table bracket, substantially in the manner as herein before described and illustrated
in the drawings.
3. The hand sockets to be attached to the stem, shank, or driving portion of the
drill provided with the device of the front flange to be used in the manner and for
the purposes substantially as hereinbefore described and illustrated by the drawings.
4. The clamp piece, formed to pass over and be secured to the tool rest of a grind-
stone, a tool grinder, with its provision for the attachment, and angular adjustment of
the front table bracket, with its concomitant arun bracket, substantially as and for the
purpose herein before described and illustrated by the drawings.
5. The combination and arrangement of parts substantially as and for the
purposes hereinbefore described and illustrated by figs. 1 to 7 inclusive of the
drawings.
6. The combination and arrangement of parts substantially as and for the purpose
hereinbefore described and illustrated by figs. 1 to 7 inclusive of the drawings,
when modified substantially as hereinbefore described and illustrated by reference to
figs. 8 to 19 inclusive of the drawings.
7. The combination and arrangement of parts substantially as and for the purpose
herein before described and illustrated by figs. 1 to 7 inclusive of the drawings when
modified substantially as herein before described and illustrated by reference to figs. 12
to 15 inclusive of the drawings.
L J
1
1000
PETER J. LIVSEY, .
Agent.