IMPROVEMENTS IN DRILLS, AND IN CHUCKS FOR HOLDING AND OPERATING THE SAME AND SIMILAR ARTICLES
Year: 1866

page_text: LETTERS PATENT to William Robert Lake, of the International Patent
Office, No. 8, Southampton Buildings, Chancery Lane, in the County
of Middlesex, Consulting Engineer, for the Invention of "IMPROVEMENTS
IN DRILLS, AND IN CHUCKS FOR HOLDING AND OPERATING THE SAME AND SIMILAR
ARTICLES." A communication from abroad by Stephen Ambrose Marse,
of New Bedford, Massachusetts, United States of America.
Sealed the 15th June 1866, and dated the 21st February 1866.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents, with his Petition and Declaration,
on the 21st February 1866, pursuant to the 9th Section of the Patent Law
Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the International Patent Office, No. 8, Southampton Build-
ings, Chancery Lane, in the County of Middlesex, Consulting Engineer, send
greeting.
WHEREAS, I am in possession of an Invention for "IMPROVEMENTS IN
DRILLS, AND IN CHUCKS FOR HOLDING AND OPERATING THE SAME AND SIMILAR

page_text: cylindrical rod of steel by the action of rotating burr cutters, said cutters
having no other motion given than their rotation, while the steel rod has given
to it a rotation on its own axis, a longitudinal movement in the direction of
its axis and toward the burr cutters, increasing from the cutting end to the
shank of the drill, and a slight recedure of the axis of the drill from the.axis
of the burr cutter as the latter cuts from the point toward the shank of the
drill. By the described movement of the cylindrical rod with reference to the
rotating cutter the spiral grooves formed are of a gaining or increasing twist
from the drill point to its shank, and as they decrease in depth toward the
shank increase in width, thereby giving free clearance to the chips made by
the drill in action. The peculiar curve of the grooves, as seen at the end of
the drill or found elsewhere in cross section of the said drill, is given by the
peculiar form of the burr cutter used. This groove may be described as niade
up of two curves, the right side of the groove, or that where the cutting edge
is formed, being nearly in the direction of a radius of the drill, while the left
or other side of the groove is a curve joining the other near the axis of the
said drill, and meeting with a quick turn the periphery thereof on the opposite
side. This form of groove gives, when the end of the drill is ground to about.
the ordinary angle, not only cutting edges which are nearly straight and
radii of the drill, but which with the surfaces of the grooves and the surfaces.
formed by grinding the drill end, are acute and are exceedingly well adapted
for cutting with the minimum of force, and offering the least possible resistance.
The drill being formed on a true cylinder it is an object to reduce the amount
of its peripheral surface, which in drilling would become frictional hearing
surface.. To accomplish this after the grooves, described have been cut
the peripheral surfaces between the grooves is cut or ground off, so as to.
leave the juncture of the right side of each groove with the surface of the
drill rod prominent and untouched, these corners or angles bearing on-
the boundary of the drilled hole and supporting and guiding the drill in its
work.
a.
The chuck for holding the drill firmly and so that the axis of each shall be
coincident is constructed as follows:-It is made of four principal parts, the
hub b, the loose ring c, the jaws d, d',. and the plate. The hub is bored at
its rear, so that like most chucks it can be fitted to the screw formed on a
lathe or drilling machine spindle, or so that it can be driven on to a centre pin
placed in such spindle and turned to fit in the holes which is bored in the rear
of the hub, all parts of which are made concentric with the said hole e. At that
end of the chuck designed to project from the lathe spindle its hub is slotted

page_text: centrally so as to receive and guide the jaws d, d³, between those parts of the
hub marked f, f¹, and this slot is cut into the body of the chuck below the
collar or. shoulder formed at g to increase the amount of holding surface for
the jaws d, d'. The ring c is made with two internal curved inclines or wedges
h, h¹, which when the ring is turned against the parts i, i, of the jaws d, d',
force them inward equally toward the centre of the chuck. The plate a which
is confined to the parts f,f¹, of the chuck by suitable screws and steady pins
leaves the ring c free to be turned by a spanner wrench, the shoulder at g
making one bearing, and the plate a the other, this being fitted into the ring
as seen in the Drawing. In the centre of the plate a there is left a hole
equal in diameter to the largest drill shank which the chuck is intended to
hold. One of the jaws d is made with a re-entering angle at the part
designed to grasp the drill shank, and the other d' is made with a salient
angle somewhat blunted. As these angles will fit into each other on their
approach to the centre of the chuck, it follows that very small drill shanks
can be grasped and held thereby, the limit of smallness of diameter being
determined only by the amount of the blunting of the salient angle. The
lengths and shape of the jaws, and the shapes and proportions of the cams or
inclines h must be such as will secure any drill, large or small, within the
capacity of the chuck in a line coincident with its axis, these shapes, lengths,
and proportions being represented in the Drawings. The jaws where they
present themselves immediately through the centre hole in the plate a are
countersunk or bevilled, so that the cone formed on the end of the drill shank
may readily separate the jaws when the parts are in the position shown in
Figure 4. When the drill shank is thus forced by hand between the jaws
all that is required to clamp the drill in exact position ready for operation is
to give the ring c a partial rotation.
Having thus described my improvements, and shewn how the same may
be conveniently and advantageously carried into practice, what I claim is,
First, a twist or spiral drill in which the grooves are so formed as to have
their curvature on that side of each groove where the cutting edge is made
nearly in the direction of a radius of the drill, so that when the cutting end
of the drill is ground to the ordinary angle cutting edges are formed, which
are straight and in the direction of radii, and present acute angled edges or
lips to the material to be drilled.
Second, a drill having spiral grooves formed to give them a gain or
increase of the spiral or twist from the point toward the shank of the
drill.

page_text: Third, the combination of the moveable jaws, inclines, and ring for holding
drills or similar tools, operating substantially as set forth.
In witness whereof, I, the said William Robert Lake, have hereunto
set my hand and seal, this Twentieth day of February, in the year of
our Lord One thousand eight hundred and sixty-six.
Witness,
T. E. JULIAN.
WILLIAM ROBERT LAKE. (L.B.)