Improvements in Mechanism for Grinding or Sharpening " Twist Drills.
Year: 1887

page_text: Date of Application, 6th Apr., 1887
Complete Left, 23rd Dec., 1887
Complete Accepted, 27th Jan., 1888
PROVISIONAL SPECIFICATION.
Improvements in Mechanism for Grinding or Sharpening "
Twist Drills.
1 WILLIAM FORD SMITH, of Gresley Iron Works, Salford, in the County of
Lancaster, Engineer and Tool Maker, do hereby declare the nature of the said inven-
tion, to be as follows:-
--
My improvements relate to mechanism by which the points of twist drills are
reduced, in order to enable such drills to commence to drill and penetrate and cut
with greater ease without being liable to travel when they begin to drill from the
true centre of the hole to be drilled, which is the case with ordinary twist drills not
thinned or reduced at the point.
My improvements consist in combinations and arrangements of mechanism by
which the points of twist drills are reduced or thinned uniformly on both sides,
leaving the point truly central, as follows, namely; the cutter or grinder is an emery
wheel or disc of suitable shape and thickness mounted upon a spindle in bearings in
a headstock which is arranged in slides so as to be adjustable in the direction of the
lengthway of the spindle.
This headstock for the spindle is mounted upon a pillar or stand which has vertical
slideways upon one face for a slide table (the upper face of which is horizontal)
which by means of a screw in suitable bearings screwing through a fixed nut, is made
to rise and fall to adjust the height of the table in relation to the emery wheel, there
being a short shaft having bearings in the vertically sliding table, which shaft by
hand wheel at one end and bevel wheels gives motion to the screw.
a
The rim of the hand wheel has a clamp upon it, which can be adjusted and then
secured in any desired position upon the rim of the hand wheel, this adjustable clamp
when the hand wheel is rotated so as to bring it against a fixed stud forming a stop,
in respect of the vertical lift of the table.
Upon the vertically sliding table horizontal slideways are formed at a right angle
to the axis of the grinding spindle, and upon these slideways a horizontal slide is

page_text: arranged to move freely to and fro, this slide having adjustable stops to limit its
movements to the desired extent.
Upon the horizontal slide a bracket is or may be mounted so as to be adjustable
upon which bracket a table with a V trough in its lengthway is formed, or it is
mounted on a horizontal axis secured in the bracket, this V trough table being at an
angle to the horizon in its lengthway and capable of being adjusted to any required
angle horizontally.
The V trough table is for the purpose of holding and presenting the twist drill to
be thinned or reduced at its point, to the emery wheel. There is a guage or stop
secured to the V trough table opposite to or against the edge of which stop or guage
the cutting "lip" of the drill is brought and is then clamped in the V trough and a
stop adjustable in the lengthway of the V trough table is then brought and clamped
against the shank end of the drill, so that when turned both sides of the point of the
drill will be acted upon in the same relative position and to the same extent.
The headstock for the emery wheel is then adjusted to bring the edge of the
emory wheel correctly over the point of the drill to be ground.
The horizontal slide is then moved to and fro to move the point of the drill under
the edge of the emery wheel, and the vertical table is lifted by rotating the hand
while the emery wheel is. operating, and when lifted to its greatest height for one
side of the drill the clamp on the rim of the hand wheel is adjusted and secured and
the hand wheel is then turned back.
The drill is now unclamped and turned to bring its other "lip" against the stop
or guage and the operation of grinding is repeated until the clamp on the hand
wheel comes against its stop or stud.
To make the mechanism act for grinding the cutting "lips" of twist drills as well
as the points, the emery wheel is changed, and the V trough table is made adjustable
accordingly to present the "lips" of the drill to the grinding surface of the emery
wheel at the proper angle. The V trough table is or may also be arranged upon a
horizontal axis to be able to give a rocking motion to the V trough table for
backing off" the cutting edges or "lips" of the drills.
"
The drills are clamped in the V trough with the lips to come against a stop or
guage and when ground on one "lip" they are unclamped and turned and again
clamped with the other "lip" against the stop or guage and then the operation is
repeated.
In place of the adjustable clamp stop on the rim of the hand wheel, there is or may
be a stop screw or other arrangement on the pillar or stand for the vertical lifting
table to come against, which can be clamped in any required position to form the
stop for the highest position of the table.
For lip grinding a stone is or may be substituted for an emery wheel and if
desired the point grinding emery wheel is or may be on a different part of the shaft
or on a different shaft to that used for the wheel grinding the cutting lips of the
drill.

page_text: COMPLETE SPECIFICATION.
Improvements in Mechanism for Grinding or Sharpening
Twist Drills.
I WILLIAM FORD SMITH of Gresley Iron Works, Salford, in the County of
Lancaster, Engineer and Tool Maker, 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 improvements relate to mechanism, by which the points of twist drills are
reduced, in order to enable such drills to commence to drill and penetrate and cut
with greater ease, without being liable to "travel" when they begin to drill from
the true centre of the hole to be drilled which is the case with ordinary twist drills
not thinned or reduced at the point.
My improvements consist in a combination and arrangement of mechanism by
which the points of twist drills are reduced or thinned uniformly on both sides
leaving the point truly central, and is illustrated by fig. 1 a front elevation, fig. 2 a
side elevation, at a right angle to that shown by fig. 1 and by fig. 3. a plan of a
machine according to my invention and also by fig. 4 a side elevation, figs. 5 and 6
are each elevations at opposite ends of fig. 4, and fig. 7 a plan view of the stand or
holder for holding the twist drills to be operated upon, shown detached.
The cutter or grinder, is an emery wheel or disc a of suitable shape and thickness
mounted upon a spindle a¹ in bearings in a headstock a² which is arranged in slides
so as to be adjustable by a screw a³ in the direction of the lengthway of the
spindle a¹.
This headstock for the spindle a' is mounted upon a pillar or stand 6 which has
vertical slideways b¹ upon one face for a slide table c (the upper face of which is
horizontal) which by means of a screw c¹ in suitable bearings screwing through a
fixed nut 6 is made to rise and fall to adjust the height of the table e in relation to
the emery wheel a,
there being a short shaft, chaving bearings in the vertically
sliding table c which shaft, by a hand wheel c³ at one end and bevel wheels at the
other end gives motion to the screw c¹.
The rim of the hand wheel c³ has a screw clamp c upon it, which can be adjusted
and then secured in any desired position upon the riin of the hand wheel, this
adjustable clamp ct when the hand wheel is rotated so as to bring it against a fixed
stud cs, forming a stop in respect of the vertical lift of the table c.
Upon the vertically sliding table c, horizontal slideways are formed at a right angle
to the axis of the grinding spindle a¹, and upon these slideways a horizontal slide d'is
arranged to move freely to and fro, dx is a rod passing between the two ends of the
slide and through an eye in the table c to keep the slide d from lifting out of its
slideways this slide has an adjustable stop which is formed by a dovetailed or
T headed bolt in a dovetail or undercut slot, and clamping screw df which stop limits

page_text: the movements of the slide d to the desired extent when it comes against the vertical
projection d secured in the table part c.
Upon the horizontal slide d, a stand or bracket e, is or may be mounted, so as to
be adjustable thereon upon which stand or bracket e, a table with a V trough e¹ in its
lengthway is formed, or it is mounted on a horizontal axis secured in the stand or
bracket e this V trough table e¹ being at an angle to the horizon in its lengthway and
capable of being adjusted to any required angle horizontally and is then secured by
the bolt ex.
The V trough table e¹ is for the purpose of holding and presenting the twist drill
to be thinned or reduced at its point to the emery wheel. There is an adjustable edge or
stop e secured to the V trough table el opposite to or against the edge of which stop
or edge the cutting "lip" of the drill is brought, and is then clamped in the
V trough by a plate e² and screws e³, and a stop et adjustable on a projection e³ in
the lengthway of the V trough table is then brought and clamped by the screw of
the stop against the shank end of the drill the end of a screw e screwing through a
projection e from the stand e is also brought under the point of the drill as a rest or
guage so that when the drill is turned and brought against the end of this screw e
both sides of the point of the drill will be acted upon in the same relative position
and to the same extent.
The headstock a² for the emery wheel a is then adjusted to bring the edge of the
emery wheel a correctly over the point of the drill to be ground. The horizontal
slide d is then moved to and fro to move the point of the drill under the edge of
the emery wheel a and the vertical table is lifted by rotating the hand wheel c³
while the emery wheel is operating and when lifted to its greatest height for one
side of the drill, the clamp c on the rim of the hand wheel c is adjusted to come
against the stud cs and is then secured and the hand wheel is then turned back.
The drill is now unclamped and turned to bring its other "lip" against or in line
with the edge or stop e and the end of the screw e', and then the operation of
grinding is repeated and continued until the clamp c on the hand wheel c³ comes
against the stop or stud c³ when both sides of the point of the drill will be reduced to
the same extent.
The clamping plate e² has one of the holes in it, for one of the bolts e³ made open
on one side, so that by slightly easing one screw the plate e² can be turned on one
side, to allow the drill to be turned or removed and replaced in the V trough.
The heads of the bolts e³ are adjustable in undercut slots one on each side of the
V trough as shown.
In place of the adjustable clamp stop e on the rim of the hand wheel c³ there is
or may be a stop, screw or other arrangement on the pillar or stand 6 for the vertical
lifting table c to come against which can be clamped in any required position to
form the stop for the highest position of the table.
<
To make the mechanism act for grinding the cutting "lips" of twist drills as well
as the points, the emery wheel is changed and its headstock turned a quarter round
in the pillar and the V trough table is made adjustable accordingly to present the
lips" of the drill to the grinding surface of the emery wheel at the proper angle.
The drills are clamped in the V trough with the "lips" to come against a stop or
edge, and when ground on one "lip" they are unclamped and turned and again
clamped with the other "lip" against the stop or edge and then the operation is
repeated.
For lip grinding a stone is or may be substituted for an emery wheel and if desired
the point grinding emery wheel is or may be on a different part of the shaft or on
a different shaft to that used for the wheel grinding the cutting lips of the drill.
Fig. 8 is a side elevation looking upon the front end, fig. 9 is also a side elevation
looking at the rear end, and fig. 10 is a plan view representing a V trough holder
with a twist drill in it for grinding the lips of twist drills.
To the slide d (or an equivalent slide) figs. 1; 2 and 3, a stand e adjustable on
the slide is secured by a bolt e*.
This stand d has a horizontal stud or axis d³ secured in it upon which the V trough e¹

page_text: is mounted so as to be adjustable to any required angle the rear end e' of the
trough, (supposed broken from the trough) being shown in two positions in fig. 9,
one above, the other below the position in which the V trough is shown completely
in full line in fig. 9.
represents a part of the emery wheel or grinding stone for grinding the lips of
twist drills, it is carried upon the spindle a¹, the headstock a² which when used for
grinding the lips of twist drills is formed with a socket to enter the hollow of the
upper end of the pillar h so as to be turned a quarter turn therein and then secured
by the set screw as shown in fig. 2, by this means the axis of the spindle a' is
brought parallel with the slide d.
The backing off of the drills after being ground or sharpened is effected by hand
grinding.
The drill, the lips of which are to be ground is fixed and adjusted and secured in
the V trough e as hereinbefore described for thinning the points; the guage es being
used for adjusting the lips but not the screw e. The other adjustments, hereinbefore
described in reference to figs. 1, 2 and 3, permit of both lips being thus truly and
uniformly ground.
.
With arrangements illustrated by figs. 8, 9 and 10 I mount a slide upon the table c
to move on the table c in a direction parallel to the axis of the headstock a² when in the
position shown in figs. 1, 2 and 3, which slide is actuated by a screw so as to give adjust-
iments to it upon the said slide, upon the table c there is a boss and centre formed for a
vertical bolt, round which a slideway corresponding to the slideway for the slide d
figs. 1, 2 and 3 is mounted so as to be adjusted at any required angle horizontally and
then be secured by the vertical bolt.
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―
1. The combination and arrangement of mechanism for thinning the points of
twist drills substantially as hereinbefore described and illustrated by figs. 1 to 7
inclusive of the drawings.
2. The combination and arrangement of mechanism for thinning the points and
grinding or sharpening the lips of twist drills substantially as hereinbefore described
and illustrated by the drawings.