Improvements in Drills and Augers.
Year: 1890

page_text: Date of Application, 23rd Dec., 1890-Accepted, 21st Feb., 1891
COMPLETE SPECIFICATION.
Improvements in Drills and Augers.
1, GEORGE HENRY SELLERS, Engineer, residing at the corner of Hinckley
and Swathunore Avenues, Ridley Park, County of Delaware, State of Pennsyl-
vania, 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 present invention especially relates to an improved twist drill or auger
formed by a rolling or forging process. The said invention, however, in its broader
sense also includes a twisted or spirally fluted drill having a central core with
flanges springing spirally from around the same however it be produced and
has its new and useful features summarized in the claims which follow this Speci-
fication.
39
The chief object of my invention is to contrive a light but stiff, strong, and
durable twist drill or anger and such a one as by its general shape and design may
be susceptible of being manufactured from a minimum of metal and in the main by
a rolling or forging process or processes. For by such preferred mode of manu-
facture I secure an abundant working of its several component parts and add to,
its even otherwise unusually great strength of form. Other objects of my present
invention being to so distribute the mass of the drill that corresponding members
thereof may be of equal cross-section at similar parts, and thereby, upon the
preferred forging mode of manufacture, better assure the homogeneity and strength
of the drill.
Other of my objects are preferably to design, contrive, and form a
" twist or
fluted drill continuous from end to end. Also to so space and form the backs of
the lands which intervene between the flutes of said drill that the same may offer
without detriment to the drill's self-acting chip relieving capacity a suitable
bearing for a chuck or other driver engagement; to make the drill, if need be,
double ended and without sacrifice of mass, and such effective distribution of the
parts as may serve to keep the drill stiff and reliable, to so fashion the lands of
the drill that they may offer a minimum of material to be dressed and ground when
pointing and edging the drill; to brace the flanges or lands of the drill by means
of merging and combining them with a central core or stiffener; and to give the
flanges such number and pitch" (rapidity of twist) as shall serve for the proper
support of their edges, and also ensure the prompt removal of chips from their
cutting faces when at work; and preferably, also to give such tapering form to
the bodies of these lands when viewed in cross-section as may serve the better
to assist their manufacture between rolls in a preliminary stage of the preferred
forging process aforesaid, together with such preferred form of the central core
and other parts as will be best understood by reference to the following detailed
description.
Reference now being had to the accompanying drawings forming part of this
Specification, in which similar letters of reference indicate corresponding parts
throughout the several figures, they will be found to illustrate my said improvement
in twist-drills as follows, to wit:
Figure 1 is a side elevation which shows the point and a portion of the shank of
one of my improved twist-drills in its preferred form.
Figure 2 is a similar side elevation of a similar drill having a modified form of
edge.
Figure 3 is a general side view of my improved drill in its preferred form with
both ends pointed and edged the point upon the right-hand extremity of the drill
being however represented as sharpened without having the cutting edges carried
:

page_text: to the extreme centre of the drill, as the edges upon the left-hand point are
represented as being.
Figure 4 is a cross-section upon a slightly larger scale of the drill shown in
Figure 3; the plane upon which it is taken being indicated by the broken
line z―a.
i.
Figure 5 is an end view of the preferred forin of cutting point, or that shown
upon the left-hand end of the drillrepresented in Figure 3.
Figure 6 is a cross-section through the body of a modified form of the drill.
Figure 7 is a side view corresponding' to Figure: 3 of a further modification
wherein there are three flanges springing from the common central core instead of
four, as are shown in all the preceding figures.
Figure 8 is a cross-section, also upon a slightly larger scale, of the drill shown in
Figure 7, by a plane passed upon the line y-y of said figure; and
Figure 9 is side elevation which shows the point and adjoining portion of the
shank of the device when specially contrived as an auger.
:
In general as shown in the figures, the drill D consists of two chief sets of
elements: one a single central and, as it were, columnar support or core D; while"
the other comprises three or more lands or flanges d d d² ³, &c., all arranged in a
series merging in and rising from the said common core. With and about which
core they all, at equal interspace and preferably uniform pitch, wind in a helix 'or
spire. The said lands being of uniform dimensions, numerous and lying parallel to.
the axis of the core, give a fluted cylindrical outline to the whole. The backs of
the lands also by approximating, if they do not actually conform to, equivalent areas
of a true cylindrical body of equal diameter, prevent the passage of the drill through
any orifice other than a circular one. That is, they prevent such passage unless
the drill shaft thus formed be rotated in conformity to the pitch of its screw-like
body when of course it may be possible to pass it through a cross-shaped opening
substantially corresponding to the profiles of its flanges and core when viewed
end wise-or, viewed as shown in Figure 5. Such opening and rotation in précise
conformity to the pitch of the screw are however, it is almost needless to say,
extremely unlike events to happen with ordinary drill feeding and driving, and
therefore the drill may, in substance, be said to be one which cannot pass through
an opening less than, or in any wise materially varying from that which it is in
point of fact calculated to bore and fashion, viz. a cylindrical or circular aperture.
While I prefer the pitch-of-the-lands. to_be_uniform, and their number to be four,
with an equal spacing of 90 degrees from centre to centre, and the cross-section
of the drill's core, as shown by dotted lines in Figure 4, to be a substantially
octagonal figure the alternate sides of which merges into, or are integral with
the base of one of the drill's flanges, as will be readily seen from reference to
that figure, do not wholly limit my improved drill's body or shaft to that
precise form or number of flanges, though I much prefer it when so fashioned.
And for the sake of further illustration I have therefore shown the modifications,
Figures 6, 7 and 8 in the former of which (Fig. 6) there is a drill of strictly
cruciform cross-section; that is to say, one the four flanges of which do not
Into which
taper as they pass outward from their common supporting core.
core they merge in this case by coves or circular arcs of small radius for 'the
sake of strength; although, of course they may, as indicated by dotted lines.
meet the same along sharp re-entrant flute angles, say of 90 degrees each. In
Figure 8 a drill of my improved sort is shown reduced to one with a substan-
tially cylindrical core having three flanges d d d³ space at 120 degrees to each
other upon any common plane of cross-section, thereby sacrificing certain of the
more meritorious features of the preferred straight or 'St. Andrew's cross sort
shown in Figures 1, 2, 3, 4, 5 and 6, for it is evident upon inspection of Figure 8
that the cutting edges of such a drill or any other in which the flanges are not
1. arranged, in. pairs, each member of which is substantially 'diametrically opposite
to its mate (or as shown in Figures 4, 5 and 6) cannot act upon what is
commonly known as the "duplex" and most advantageous method of cutting
1
!ן

page_text: t
with drills and boring tools, for keeping them. true to an established, line of
advance. However, Figures 7 and 8 illustrate a drill, which will be found in
practice to operate with many advantageous results, and in common with
Figures 1, 2, 37and.5 shows how my improved boring device, whatever the
number of its flanges or the shape of its core, may be, can be advantageously
pointed and sharpened for metal working or shaping, or as a. drill proper. :
12.
Ipreferably make the drill orhauger as above alluded to from a "billet of
"tool-steel" (or such steel as is proper to make an ordinary edged tool from)
and by any suitable forging operation, such as-taking a sufficient heat upon the
billet, and passing it one or more, times through a suitably formed, groove, or
grooves in a nest or rolls, fashioning it into a straight blank of, uniform shaped
cross-section throughout its length; and then, and if possible at the same heat,
twisting this straight blank to a proper pitch and multiple thread, screw-like
form of twisted blank which is now substantially clear.. This latter act of
twisting the blank may also be done by a good smith with a mere vice and
tongs, or wrench-held, and give fair results. And finally as a completion of the
forging preferably straighten and size such incipient drill or auger blank by
for instance rolling the same between a relatively adjustable platen and a
reciprocating pressure plane, plate. Otherwise I have fashioned these blanks by
planing or milling out the flutes,, and so obtaining either a straight or appro-
priately spiral blank, and according to its straight or twisted character, at this
stage, subsequently proceeding in substantially the like manner as
preferred forging method. The pitch of the spire is, I find, with, a drill of one
inch diameter and four flanges, best if of about. two and one-half inches ;
however it may be. more or less steep, and if need be, as is well understood by
twist-drill and auger makers, of gaining or non-uniform pitch. The final stages in
all cases consist of pointing or otherwise dressing the, working end or ends of the
drill or anger to an appropriate shape, then hardening, tempering, and edging the '
same in order to produce the completed article.
in the
The pointing for drills preferably is, a conical one, say 60 degrees; and. the
sharpening which of course is done after the drill has been wrought, hardened,
tempered, and otherwise prepared in a proper manner of the production of drills, is
best effected as I contrive it by grinding upon the flange's extremities proper angles
of relief and cutting edges, and, further preferably supplementing the length of the
drill's several flange's cutting edges by carrying these edges e in a prolongation of
each curved flange forward to the centre of the core, as by means of what I may
call "concoidal" recesses c ground into the coned point of the core D. This will
be easily understood by referring to Figures 1 and 5 where the mode of sharpening
is the proper one for boring into iron or steel, and where the core of the drill is
shown by such recesses c fashioned in the manner of a rose-drill. By this means
the cutting edges are made to seek and converge in a common centre; which of
course, materially facilitates the ease with which the drill may be fed. However,
referring to the right hand extremities of Figures 3 and 7 the drill will be seen, in
both the three and four flauge varieties, to be sharpened in such way as to have the
edges and "faces of relicf" terminating short of the central core: which is here,
save only for the quasi cutting action of the somewhat pyramidal arrangement
of the point of the core, necessary to force through the work without the best
cutting action. In which respect the drill more nearly corresponds to the
action of ordinary drills than does it when fashioned with the preferred rose-
sharpening aforesaid.
In Figure 2 the rear walls of the flanges are not ground away with relief faces
but the front flanges are truncated by grinding them transverse to the general
mass of each particular flange-thus giving the requisite obtuse sharpening proper
for boring into brass and similar material. The core D', in this case is also dressed
away in the region of the point to a cylindro-conical, or rifle bullet like shape, thus
giving a chance to grind the cutting edge of each flange to approximately its point
of common intersection with the others."

page_text: A striking advantage flowing from the uniformity of my improved drill or auger's
mass, as aptly illustrated by the typical cross-section shown in Figure 4, resides in
the fact that thereby the hardening and tempering processes act uniformly and
equally throughout the whole body of the drill and if broken away at its edges it
may be quickly repaired by a mere grinding.
For an auger an appropriate form of pointing is shown in Figure 9 where the
blank is here represented as having had its flanges dressed or cut back from the
leading end of the core which, so far as it protrudes, is fashioned into an ordinary
auger-like head screw point S. The cutting edges e of the flanges shown in
Figure 9 are also here of proper acuteness to act upon wood and reference to the
general mass of the drill, are located at a preferred square position to the core D'
and all in a common plane. The edges may also, as indicated by dotted lines
at KK, have marginal guide lips in the manner of ordinary augers; but with the
preferred four-flange sort this is I find an almost unnecessary addition.
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:
First As a new article of manufacture, a twist drill consisting of a central core,
and fashioned integral therewith, and rising therefrom at substantially equal inter-
space, three or more flanges of similar width, the whole spirally twisted and adapted
to be pointed and sharpened, substantially as described.
Second: As a new article of manufacture, a twist drill consisting of a central
core and three or more helically-wound flanges rising integral therefrom and con-
tinuously along the same from end to end, substantially as described.
:
Third As a new article of manufacture, a drill consisting of a single forged
body comprising a central core of substantially octagonal cross-section, as described,
and rising therefrom and merging therewith upon alternate faces of said octagon
similar and outwardly-tapering flanges, the whole being helically twisted, and
adapted to be pointed and sharpened at one or both ends, substantially as
described.
:
Fourth As a new article of manufacture, a drill consisting of a single forged
body comprising a central core of substantially octagonal cross-section, as described,
and rising therefrom and merging therewith upon alternate faces of said octagon,
similar-and-outwardly-tapering flanges, the whole being helically twisted, pointed
and sharpened, the latter by fashioning suitable cutting edges-and--relief...faces
upon the ends of said flanges when pointed, and also by carrying the same to a
common centre by means of recessing or rose-pointing the said core, substantially
as described.
11
37 1 1
1
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.