Improvements in Drills and in Holders therefor.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Drills and in Holders therefor.
I, WILLIAM FREDERICK BEARDSHAW, of Baltic Steel Works, Sheffield, Manu-
facturer, do hereby declare the nature of this invention to be as follows:-
In straight and twist drills it is desirable that the point or apex should be
central. When regrinding this is at times difficult to attain, and to aid in securing
the desired result it has heretofore been proposed that the centre line of the drill
should be marked by a cut or scratch. Again when the drill has been formed of
metal having a cross section that might be termed double bulb, triangular, or
other than round, difficulty has been experienced in securing a satisfactory and
economical holder for the drill.
According to this invention not only is the centre line to which the point may
be ground clearly defined but also a holder is produced capable of being used in
most of the drilling machines now commonly employed.
To this end it is proposed that the double bulb or other section of metal should
have produced upon it while being rolled ribs or projections centrally located as
between the outer faces of the metal, while the holder is formed on its inner faces
with slots adapted to receive such ribs and being otherwise shaped so as to closely
fit the section from which the drill is formed, the thickness or external face of the
holder being so shaped as to form when upon and with the drill a circular, taper
or like shank the top of which may be partly cut away permitting a portion of the
drill to pass therethrough so that the twisting or torsional strain will fall in part
directly upon the drill."
1
די
1000
i, WILLIAM FREDERICK BEARDSHAW, of Baltic Steel Works, Sheffield, Manu-
facturer, 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:-
· In straight and twist drills it is desirable that the point or apex should be

page_text: central. When regrinding this is at times difficult to attain, and to aid in securing
the desired result it has heretofore been proposed that the centre line of the drill
should be marked by a cut or scratch. Again when the drill has been formed of
metal having a cross section that might be termed double bulb, triangular, or
other than round, difficulty has been experienced in securing a satisfactory and
economical holder for the drill.
According to this invention not only is the centre line to which the point may
be ground clearly defined but also a holder is produced capable of being used in
most of the drilling machines now commonly employed.
To this end it is proposed that the double bulb or other section of metal should
have produced upon it while being rolled ribs or projections centrally located as
between the outer faces of the metal, while the holder is formed on its inner faces
with slots adapted to receive such ribs and being otherwise shaped so as to closely
fit the section from which the drill is formed, the thickness or external face of the
holder being so shaped as to form when upon and with the drill a circular, taper
or like shank the top of which may be partly cut, away or recessed to permit a
portion of the drill to seat therein so that the twisting or torsional strain will
fall in part directly upon the drilling machine or tool.
To clearly explain my invention I have shown in the accompanying drawing
one manner of carrying same into effect.
In this drawing-
Fig. 1 is a front elevation of a plain untwisted bar.
Fig. 2 is a section of same.
Fig. 3 is a side elevation of a twisted bar.
Fig. 4 is an elevation of a holder and drill.
Fig. 5 is a section on line
of Fig. 4.
Fig. 6 is an elevation of a holder and drill to show a modification.
Fig. 7 is a plan of the holder and
Fig. 8 is a plan of the drill.
In the drawings a represents the central rib or projection which when the drill
is sharpened will form the apex of the point and thus afford a guide or assistance
to the proper grinding of same. Such ribs or projections may be of various shapes.
When the drill is twisted a plain untwisted portion is preferably left at one end
and it is this part which is adapted to be held by the holder above referred to.
This latter consists of a solid portion c suitably shaped to be held by the tool in
which it is to be used, said solid portion being slotted or provided with two open
jaw pieces d d the inner faces of which are curved as at to correspond with the
curvature or section of the drill, the jaws in cases where a central rib a of the shape
shown is employed being also recessed as at d³ to receive such rib.
To further hold and steady the drill in the holder and to cause some of the strain
to be taken by the tool itself instead of entirely by the jaws d I may form a recess e
in the upper part of portion c of the holder as shewn in Fig. 7 in which will fit
a reduced portion or projection f of the drill as shewn in Fig. 8, the parts together
being shewn in Fig. 6. It will be seen that as the upper part c of the holder is
held by the tool the portion f inside same will transmit the strain directly to the
latter.
By suitably shaping the jaws of the holder, drills of triangular and many other
sections may be held, the construction of holder being simple and enabling the
drill to be easily inserted and withdrawn and to be firmly held in same.
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. A drill provided with a central rib or projection substantially as and for the
purpose described.
2. A drill holder provided with open jaws the interior surfaces of which are

page_text: shaped to correspond with the drill and to hold same substantially in the manner
described.
3. The improved construction of drill and drill holder substantially as described
and illustrated
shaped to correspond with the drill and to hold same substantially in the manner
described.
3. The improved construction of drill and drill holder substantially as described
and illustrated
Dated the 20th day of December 1898.
PHILIP M. JUSTICE,
Chartered Patent Agent, 55 and 56, Chancery Lane, London,
For the Applicant.