Improvements in and relating to Apparatus for Grinding Twist and other Drills.
Year: 1888

page_text: Date of Application, 15th Sept., 1388
Complete Specification Left, 15th June. 1889-Accepted. 10th Aug.. 1889
PROVISIONAL SPECIFICATION.
Improvements in and relating to Apparatus for Grinding Twist
and other Drills.
We JOHN HENRY STOREY of 37 Farringdon Street in the City of London
Engineer and HENRY JESSE BAMFORD of 61 Somerville Read New Cross in the
County of Kent Engineer do hereby declare the nature of this invention to be as
follows
This Invention relates to a Machine or apparatus for grinding twist and other
drills, and consists in mounting a grinding wheel of any suitable material on a spindlo
carried by a lever which pivoted at or near one extremity or other suitable point
to a disc. This lever is also fulcrumed at a suitable point to one end of a link the
other end of which is anchored or connected to a pin which is fitted to the frame or
body of the machine or to a suitable bracket attached thereto. This anchorage pin
may be fixed but it is preferably carried on a lever which is provided with a tooth
sector and screw adjustment or it may consist of an eccentric with any suitable
adjusting and clamping device or any other suitable means may be provided for
raising lowering or otherwise adjusting the fulcrum or centre of suspension of the
said lever and link whereby the desired amount of clearance or rake technically
known as * Backing off" may be given to the cutting nose of the drill automatically
in the one operation of grinding.
The said disc is fitted to a suitable frame or socket and is free to oscillate or turn
therein so that the centre of the lever pivot moves in a path concentric to the centre
of rotation or oscillation of the said disc and at a suitable radius therefrom. A crank
may be substituted for the disc and the frame or socket in which the same works
may be either rigidly fixed to the main framing or body of the machine or it may
be made adjustible. In the latter case the said link is anchored to a fixed point and
the amount of clearance or " Backing off" given to the cutting nose of the drill is
regulated by adjusting the said frame or socket in which works the disc or crank or
the clearance may be effected by making both the said frame or socket and the said
link adjustible. Or they may be both fixed in which case the clearance or
backing off" is effected by causing the centre or axis of the drill to vertically
approach or recede from the centre or axis of rotation of the said disc or crank.
"
Obviously a suitably formed cam or path in or upon which the pivot of the said
lever works may be substituted for either the disc or crank.
The drill is fixed in a V or other suitably formed rest by means of clamps and
screws or other convenient device. The rest is provided with an adjustible stop
which bears against the flank of the drill and keeps the drill in position so that both
flanks are ground accurately in relation to the axis of the drill. The said rest may
be mounted on an arm or bracket which is fixed to the body of the machine at a
suitable angle for grinding the nose of the drill. Or it may be made adjustible for
grinding the nose of the drill to any required angle. The rest may be also provided
with a suitable feed motion for advancing the drill against the wheel. And it may be
fitted with a vertical adjustment for the purpose of regulating the amount of clearance
or "Backing off" as above referred to.
The grinding wheel and lever are operated and controlled together by means of
handles provided for that purpose and the wheel is constrained to move in a parabolic
or other suitable path about the nose of the drill by means of the devices above
described. The amount of clearance or "Backing off" depends on the position which
the drill occupies vertically in relation to the said path of the grinding wheel. The
relative positions of the drill and path may be varied in the manner described.
September 15th 1888.

page_text: COMPLETE SPECIFICATION
Improvements in and relating to Apparatus for Grinding Twist
and other Drills.
We, JOHN HENRY STOREY, of 37 Farringdon Street, in the City of London in the
County of Middlesex, Engineer, and HENRY JESSE BAMFORD of 61 Somerville Road,
New Cross, in the County of Kent, Engineer, do hereby declare the nature of this
invention to be particularly described and ascertained in and by the following
statement :-
Our invention relates to a machine or apparatus for grinding twist and other
drills, and it has for its objects effecting the grinding of the drills in a simpler and
more ready manner than has hitherto been attained, and also of regulating the
amount of clearance or rake technically known as "backing off" to be given to the
cutting noze of the drill.
We attain these objects in the manner illustrated in the accompanying drawings
in which Figure 1. Sheet No. 1. is a view in perspective of our improved machine.
Figure 2. Sheet No. 2. is a view in side elevation of the rest or arm for carrying the
drill to be ground. Figure 3. Sheet No. 2. is a view in transverse section of the
rest or arm showing the clamp for fixing the drill. Figure 4. Sheet No. 2. is a
view in end elevation of the rest or arm showing the adjustable stop for defining the
position of the flank of the drill so that both flanks are ground accurately in relation
to the axis of the drill. Figures 5 and 6. Sheet No. 2. are views in side and front
elevation respectively of the grinding mechanism, and Figure 7. Sheet No. 1. is a
plan thereof.
Throughout these views similar parts are marked with like letters of reference.
The grinding wheel A which may be of emery or other suitable material is mounted
on a spindle a carried in a bearing & forming one end of a lever B, which is pivotted
at its other end to a pin e mounted eccentrically on a disc C which is mounted so as
to be capable of rotating smoothly and easily in a strap or sheath O' fixed to the
stand X of the machine." At or about the centre of its length the lever B is pivotted
by a pin to one end of a link D, the other end of which is anchored by means
of a pin or stud d to a bell crank lever D' which is fulcrated to the frame X of the
machine by a pin or stud d. The lever D' is fitted with any suitable clamping
device whereby it can be fixed to the frame when the point of anchorage of the
link is determined, to give the desired amount of clearance or "backing off" to the
cutting nose of the drill.
If desired any other suitable device, such as a hand lever and slide, hand wheel and
screw, toothed sector lever or an eccentric may be used, for adjusting the position of
the anchorage of the link D whereby the desired amount of clearance or "backing off"
is given to the cutting nose of the drill.
It may be sometimes found convenient to regulate the amount of clearance or
t: backing off" to be given to the cutting nose of the drill, by anchoring the link D
direct on to the frame X and mounting the strap or sheath C on the frame X in such
a manner that the position of the eccentric in the vertical plane may be varied, or it
may be effected by making both the strap or sheath, and the point of anchorage of
the said link, adjustable with respect to the frame, or on the other hand they may
both be fixed and the clearance or "backing off" be effected by causing the centre
or axis of the drill to vertically approach or recede from the centre or axis of rotation
of the disc C mounted in the said strap or sheath.
Instead of pivotting the end of the lever B to the disc as shown in the accompanying
drawings, it may be pivotted to a disc mounted on an axle carried in long bearings,
or it may be pivotted to a crank, or as a substitute for both the disk and crank, a
suitably formed fixed cam may be used to give the desired path of motion to the end
of the lever B. To manipulate the grinding wheel one or more suitable handles C
are provided. If one only is used it is fixed to the pin e carried by the eccentric C
as illustrated. If a second handle is used it is fixed to the front of the bearing b of
the lever B.

page_text: The drill to be ground is fixed in a V-shaped rest. E by means of the clamp F
operated by a screw f and hand wheel E¹. A butt clamp Ġ is also provided for the
end of the drill to bear against. Both these clamps are adapted to be adjusted in any
position on the rest E by means of their respective screws f and g, and hand
wheels F and G₁ as illustrated by Figures 2. and 3. Sheet No. 2. of the accom-
panying drawings. On the end of the rest E is also mounted a stop I adapted to
be adjusted by means of a clamp nut H, or its equivalent, as illustrated by
Figures 2. and 4. Sheet No. 2 of the accompanying drawings to bear against the
flank of the drill and so keep it in position and ensure- -when the drill is turned for
the purpose of grinding the other flank that it is fixed in the right position for
accurately grinding both flanks in relation to the axis of the drill. The rest E is
mounted on an arm or spindle J¹ which may be either fixed to the frame X of the
machine in the correct position for grinding the nose of the drill to the desired
angle, or it may be mounted on a slide capable of being. laterally adjusted with
respect to the frame of the machine as illustrated by Figure 1. Sheet No. 1, by means
of a screw and suitable hand wheel or by any other equivalent device. The rest E
is fitted with a traversing screw e and hand-wheel E' or with any other suitable feed
motion whereby the drill may be advanced against the grinding wheel.
tr
As hereinbefore mentioned the clearance or backing off" may be effected by
causing the centre or axis of the drill to vertically approach or recede from the centre
or axis of rotation of the disc or its equivalent mounted on the frame of the
machine. In this case the rest E is adapted to receive a vertical as well as a
horizontal feed motion so that the centre or axis of the drill may be adjusted as
desired. This vertical motion may be effected in any suitable manner.
Motion
Motion is imparted to the spindle a carrying the grinding wheel, from a counter-
shaft K by means of a belt running over pulleys as illustrated by Figure 1.
may be imparted to the counter-shaft in any approved manner.
It will be seen that in operation the drill is a fixture in the rigid rest E and
does not move, but that the grinding wheel is constrained to move in a parabolic
path, about the nose of the drill by reason of the manner in which the grinding
wheel is mounted, and its movement is controlled as herein before described. We
wish it to be clearly understood that we do not limit ourselves to the exact details of
construction hereinabove set forth but hold ourselves at liberty to make such changes
and alterations as fairly fall within the spirit and scope of our invention. It will
be further understood that the amount of cicarance or backing off" given to the
cutting nose of the drill will depend on the position which the centre or axis of
the drill occupies vertically with respect to the path of motion of the grinding
wheel.
<
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is
1st. A grinding machine for grinding twist and other drills, constructed, arranged
and operating as set forth.
2nd. In a machine for grinding twist and other drills, giving the clearance or
backing-off" to the cutting nose of the drill automatically in the one operation of
grinding, in the manner set forth.
3rd. In a machine for grinding twist and other drills, mounting the grinding
wheel on the end of a lever adapted to oscillate on a link anchored or pivotted to the
frame of the machine, and controlling the movement of the said lever by means of an
eccentric, crank, or can, as and for the purpose set forth.
4th. In a machine of the type herein before described for grinding twist and other
drills, adjusting the position of the point of anchorage of the link supporting the
lever carrying the grinding wheel in the manner described and illustrated by.
Figures 5 and 6. of the accompanying drawings.
5th. In a machine for grinding twist and other drills, the combination with the
rest E and the clamps F and G for holding the drill, of the adjustable stop H for

page_text: ensuring the correct fixing of the drill for grinding the flanks thereof in accurate
relation to one another and to the axis of the drill as set forth.
6th. In a machine for grinding twist and other drills, the combination with the
rigid rest E having suitable clamps for fixing and holding the drill and a suitable
stop for regulating the correct positions of the drill for grinding the flanks thereof,
of the lever B suspended at or about the centre of its length from an anchored link,
and pivotted at one end to an eccentric or its equivalent whereby the grinding wheel
carried at the other end of the said lever is constrained to move in a parabolic path,
as and for the purpose set forth.
רזי
1 day of 0.
ROBT. ED. PHILLIPS, M.I.M.E.,
Consulting Engineer and Patent Agent,
Royal Courts Chambers,
70, 71 & 72, Chancery Lane, London, W.C., Agent for the Applicants.