Improvements in Drills.
Year: 1890

page_text: Date of Application, 4th Nov., 1890-Accepted, 6th Dec., 1890%
COMPLETE SPECIFICATION.
Improvements in Drills.
I, JOHN MUIRHEAD, of Pittston, Luzerne County, Pennsylvania, United States of
America, 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 improvements in drills, and consists first of a drill having a
stem with enlarged portions, the latter having a tapering opening, and a groove
leading into the said opening in combination with a bit adapted to be held in the
said opening and groove, second, of a drill having a screw-threaded portion of its stem
provided with a movable guide block, the latter being held in place by a key, sub-
stantially as hereinafter described, and third of the combination of the several parts
as hereinafter described.
In the accompanying drawing,
Figure 1 represents a side view of a drill having a tool holder with bits, and a
guiding block, embodying my invention.
Figure 2 represents a central longitudinal sectional view of the device shown in
Figure 1.
Figures 3 and 4 represent cross sections on lines, c, and y, y, respectively,
Figure 1.
Figure 5 represents a perspective view of one of the bits.
Similar letters of reference indicate corresponding parts in the several figures.
A designates a drill consisting of the holder B, the stem portion C; the guiding
block D, and the bits E.
The holder B is formed of the enlarged portions F and G of the stem, the larger
portion F having a series of conical or tapering openings H therein at. equal distances
from the centre of the stem, and the smaller portion G having the grooves J, the
said openings and grooves extending in the same direction, and being adapted to
receive respectively the tapering necks K, and the back portion L of the bits E.
The shouldered portions M of tlie bits are in contact with one side of the said larger
portion F, and on the screw-threaded ends K', of the necks K are the clamping
nuts N, which bear against the holders B, and reliably retain the bits in their place
therein.
The bits E have enlarged or widened front or outer portions P, and the bevelled
faces of their cutting edges are the widest at the outer edge of the bit, as at Q, the
said cutting edges extending beyond the periphery of the holder.
The upper end of the stem C is provided with the usual head R, and a screw thread $
for securing the drill to its operating mechanism.
The lower end of the stem has a screw-threaded portion T on which is secured the
many sided guiding block D, by means of the key U, which latter is seated in the
slot V of the stem, and the recess or groove X of the said block D.
When it is desired to place a bit in the holder, the tapering neck K is inserted
in an opening H, the back of the bit being in the adjacent groove J, and the bit is
pushed so that the threaded portion K' of the neck K projects from the holder when
à nut N is secured thereon, so as to clamp said bit in proper position.
In releasing the bit, the nut is first removed from the neck, and the bit is pushed
outward in the line of the groove, so as to remove the neck from the opening, and
thereby permit its release from the holder.
In operating the device, the end of the stem having the guiding block D is first
inserted in a small opening, suitably formed in the article to be drilled, so that the
said block 1) may serve as a guide for the drill in its reciprocating as well as rotary
motion.

page_text: It will be seen that with bits formed and secured as herein described, a hole or
opening of uniform diameter may readily be drilled in any suitable material, the said
hole also having its walls extending in the same direction.
Owing to the front or outer portion of the bit being the widest, the extra wear and
greater strain which is at the outer part of the cutting edge is provided for.
In some cases it may be desirable to attach or secure the guiding block D to the
stem C in an immovable manner. This may be accomplished by welding said block
to the stem.
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 1
claim is
First. A drill having a stem with enlarged portions forming a tool-holder, one of
said portions being provided with a tapering opening, and another with a groove
leading from said opening in combination with a bit having a tapering neck adapted
to fit in the said opening, and a back adapted to fit in said groove substantially as and
for the purpose set forth.
Second. A drill having a stem with enlarged portions forming a tool-holder, one of
said portions being provided with a tapering opening, and another with a grooved
bead from said opening, in combination with a bit having a thickened front or outer
portion, and a tapering neck or shank forming a shoulder with said outer portion,
and thereby providing a cutting edge of greater width than the neck or shank, sub-
stantially as described.
Third. A drill having on its stem a screw-threaded portion at or near one end
thereof, a movable block on said screw-threaded portion of the stem, and a key seated
in a slot in said stem, and in a recess in, said block, substantially as described.
Fourth. A drill having a stem with an enlarged portion with an opening therein,
and a smaller portion having a groove therein and a bit with a neck fitting in said
opening, and a back in said groove, substantially as described.
Fifth. A drill it having a tapering neck with a shoulder a thickened front or
outer portion; and a cutting edge of greater width than the shank thereof, substantially
as and for the purpose set forth.
Sixth. A drill having on its stem a guiding block, substantially as and for the
purpose set forth.
Dated this 4th day of November 1890
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.