Improvements in the Manufacture of Twist Drills and other like Grooved Tools, and in the Holders for same.
Year: 1893

page_text: Date of Application, 19th July, 1893
Complete Specification Left, 19th Apr., 1894-Accepted, 25th May, 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Twist Drills and other like
Grooved Tools, and in the Holders for same.
I, WILLIAM LOCKWOOD of City Standard Piston Works, Bramall Lane,
Sheffield in the County of York, Engineer, do hereby declare the nature of my
invention to be as follows:-
My invention relates to the manufacture of longitudinally grooved drills,
rimers, taps and such like tools referring more particularly to twist drills and to a
special holder for same.
I propose in the manufacture of such drills having two or more grooves, in the
first place to prepare a pair of rolls with annular grooves and rings of any of the
various required sizes, and to pass the bars of steel through such rolls until I
produce a round bar or rod with straight longitudinal grooves of the required size
and form.
I then propose if the rolled bar is not finished as accurately as it should be to
draw the bar through a tight fitting wortle to give a finished form and surface, and
after hardening to grind and glaze as may be preferred. I then cut the bar or rod
so made into short lengths, and twist them to the desired curve, this may be
effected in various ways, such as forcing the grooves between fixed studs set at an
angle, or passing the bar through a loosely fitting rifled wortle.
Where drills are required with a plain cylindrical shank, the grooves will be
rolled in by means of a pair of eccentric rolls, arranged to seize the bar or rod
(already cut off to the desired length) below the shank, in the manner known to
engineers and to those who use eccentric rolls for other purposes.
The twist drills made in the manner hereinbefore described as being cut off a
previously grooved bar, will be grooved from end to end including that part called
the shank which is passed into the nozzle of the drilling machine, and to hold the
drill so made securely and centrally I have constructed a holder for same, as
follows.
I prepare an externally screw threaded socket having a conical interior, the top
of the socket is tapered and terminates with a short paralled screwed part, the taper
and the screw being intended to fit into corresponding parts in the nozzle of the
drill spindle.
In the conical interior of the socket, the large end of which opens downwards, I
fit a number of jaws say for example three, the outsides of the jaws being made
convex to fit against the conical interior, and the inside faces being concave to fit
upon the drill.
In some cases I make the inside face of the jaws with a twisted projection to fit
into the groove of the drill to ensure a perfect grip.
To retain the jaws in the conical interior of the socket and to cause them to come
together by forcing them into the smaller end of the cone, I screw upon the
externally screwthreaded socket from the underside, a cap with a central opening
small enough to prevent the passage of the jaws, but which when screwed up forces
the jaws into the cone and contracts the hole for the drill.
Dated the 15th day of July 1893.
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicant.

page_text: Improvements in the Manufacture of Twist Drills and other like
Grooved Tools, and in the Holders for same.
I WILLIAM LOCKWOOD of City Standard Piston Works, Bramall Lane
Sheffield in the County of York, 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 the manufacture of longitudinally and spirally grooved
drills and other similarly grooved tools, and to a specially constructed holder for
same.
The invention or those parts that require it are illustrated in the annexed sheet
of drawings in which
Fig. 1, represents a bar of round steel.
Fig. 2, the same bar with longitudinal grooves.
Fig. 3, holder and nozzle of drilling machine shown in section.
In carrying the invention into practice so as to produce a drill having two or
more grooves, two being the usual number, prepare a pair of rolls such as
in general use having annular grooves and rings of the desired size and form
and I pass a heated bar of steel as Fig. 1, through the said rolls either one or
more passes, until I have produced a grooved bar such as shown in Fig. 2, for
example.
If desirable to give a more perfect finish to the surface of the grooved bar, I
may submit it to the action of a reeling machine, or I may pass it through a wortle
or drawplate either with or without projecting parts to fit into the grooves. I then
cut the grooved bar into the desired lengths for drills, and twist them to the
desired curve; this may be effected in various ways such as forcing or pulling the
grooved bar through a rifled wortle or drawplate.
When such drills are required with a plain cylindrical shank, I produce the
grooves by a pair of suitably formed eccentric rolls, arranged to seize the short
heated rod below the position of the shank, rolling the grooves from that point
to the end after the manner of eccentric rolls, and then producing the twist as
before.
Or instead of rolling or producing the grooves by a revolving pressure, I may
produce the grooves in the first stage by direct pressure, as for example under the
hydraulic press.
The drills made as hereinbefore described are then finished in the usual manner.
To hold these drills securely and centrally when being used, I have constructed
a special holder for same, as follows and with reference to Fig. 3.
make an externally screwthreaded socket A, with a conical interior B, the
upper part of the socket being tapered at C, and terminating in a short screw D,
these two latter parts C, and D, being to fit into the nozzle of drilling machine
spindle E.
Into the coned part B, of the socket A, .I fit a number of jaws F, preferably
three, the outside of the jaws being convex to fit the conical interior, and the
inside of the jaws being made concave to fit upon the drill G.
In some cases I make the inside concave face of the jaws with a projection to fit
into the groove of the drill to ensure a more perfect grip.
To retain the said jaws within the conical socket, and to cause them to close
upon the drill I screw upon the externally screwthreaded socket A, from the
underside, a cap H, having a central opening I small enough to prevent the passage
of the jaws F, which would otherwise drop out of the socket.
When this cap is
screwed upon the socket it forces the jaws upwards into the coned interior B,
drawing them together, and reducing the centre hole or drill space.

page_text: 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. In the manufacture of twist drills and other like grooved tools, producing the
longitudinal grooves in bars of steel either by rolls, having a rotary motion, or by
tools having a direct pressing action, and afterwards twisting the grooved steel, as
hereinbefore described.
2. The manufacture of twist drills and other similarly grooved tools by first
grooving the plain bar by rotary or direct pressing tools, and secondly by twisting
such grooved bars and finally finishing them for use.
3. As a means for holding securely and centrally the above or other like drills,
a nozzle with expanding and contracting jaws constructed as hereinbefore described
and substantially as shown in the drawings.
Dated the 17th den of Anmil 1804
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicant.