Points of Wood Screws.
Year: 1887

page_text: Points of Wood Screws.
I, CHARLES DAKE ROGERS of Providence County of Providence State of Rhode
Island U.S.A. Mechanic, 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 :-
This invention relates to an improved method of shaping and screw-threading
the points of Wood Screws, and consists in passing the screw blank between dies, the
action of which is to first roll or impress a partly formed thread into the body of the
shank and at the same time roll the rough point of the blank into shape preparatory to
being threaded, the continued action of the said dies completely forming the screw-
thread, both on the shank and pointed portions of the screw.
It also consists in the novel construction of the dies, and mechanism for operating
them.
Wood screws as commonly screw-threaded are first passed through a pointing
mechanism which gives a proper form to the point of the blank. This operation
becomes necessary when the blanks are severed from the rod by shearing, or
<< pinching," from the fact that more or less of a burr or fin is left on the point. It
is evident that the employment of such pointing mechanism, when in a separate
machine, including the attendance of an operator, necessarily increases the cost of
manufacture.
Moreover, where rolling-dies are provided with thread-forming ribs adapted to

page_text: thread the point of a screw (not previously prepared) coincident with the forming of
the thread on the shank of the screw the reduction of the metal of the pointed end
and its consequent elongation produces additional strains upon the dies, the same being
due to the opposed action of the metal of the screw in flowing both laterally and
longitudinally at the same time.
The screws thus produced are found to be inferior, owing to the fact that the
thread on the point is rough, in some instances being only partly finished while in
others the threads are nearly or quite detached at the root from the core due to the
cause stated, wherein in forming the thread the unyielding ribs and grooves of the
dies retain the stock impressed therein, but the end of the screw while being rolled
into shape is elongated, thereby causing the metal to "quarrel," as it may be
termed.
The object of my improvements is to overcome these disadvantages, and produce a
superior wood-screw at a reduced cost.
These results I attain by the use of peculiar dies, each of which for a portion of its
length at the lower or point-forming portion (and at the entering end thereof) being
without grooves, and having a form adapted to roll and elongate the pointed end of
the blank to a uniform shape. This plain or ungrooved portion merges into a
correspondingly shaped portion of the die into which obliquely arranged grooves,
uniting with the main threading grooves, are cut adapted to roll a thread on the
screw point while the screw shank is being completely threaded.
The dies are provided at the lower contiguous edges with an extension or cutter
adapted to sever from the point of the screw any superfluous stock remaining after
the thread is formed thereon.
The shape of the thread-forming ribs, adapted to produce a solid screw-thread
raised from the surface of a screw blank, is shown and claimed in an Application for
Patent, filed by me, September 20th, 1887.
In the annexed two sheets of drawings, Figure 1, Sheet 1, represents, in elevation,
the working face of one of a pair of dies constructed substantially according to my
present invention.
Fig. 2 is a transverse sectional view, taken through a pair of said dies, corresponding
to line o o, Fig. 1. Figs. 3 and 4 are similar views taken through lines and u u,
of Fig. 1, respectively. Fig. 5 is a perspective view of a headed screw blank, as
roughly severed from a rod, as usual. Fig. 6 is a similar view of the lower portion of
a blank, showing "fins" formed thereon by the action of the cutting-off dies.
Figs. 7, 8, and 9, represent perspective views of the screw-blank, corresponding to
the several stages in rolling the thread by the dies, at the lines 88, xx, and uu
respectively. Fig. 10 is a plan view of a machine having my improved dies mounted
therein, and adapted to shape the point of a screw-blank and to roll a screw thread
into the shank and point of the blank. Fig. 11 is a transverse sectional view taken
on line of Fig. 10, viewed from the left.. Fig. 12 (Sheet 2) is a side elevation of
the working face of my improved die. Its lower edge being divided into three parts
or sections, viz. :-the first part being adapted to roll the point of the blank into
proper form, preparatory to being threaded and simultaneously with the commence-
ment of the forming of the threads on the body of the blank, the second section being
constructed and adapted to roll the screw-thread on the pointed portion of the screw,
and the third section is composed of a knife or cutter adapted, in conjunction with its
fellow die, to remove any superfluous stock from the tip of the point which may have
been produced during the rolling process.
Fig. 13 is a transverse sectional view of a pair of mounted dies provided with such
cutting edge, taken on line m m of Fig. 12; and Fig. 14 is a perspective view of a
partly finished screw showing superfluous metal extending from the tip thereof as a
result of shaping and screw-threading the point.
In the drawings A (Fig. 1) designates my improved die, made of steel and
hardened. The working face of the die is provided with a series of obliquely arranged
thread-forming ribs a, separated by grooves b. The lower-edge portion of the die is

page_text: beveled or angular, as at k; a portion, 61, thereof for about one-third of the length of
the die, from the entering end a', is made smooth or ungrooved. This plain portion
is adapted to reduce the roughened point of the blank, as p (Figs. 5 and 6), into the
proper symmetrical form necessary, and preparatory to the point's engagement with
the thread forming portion, 63, of the die, about to bo described. The superfluous
metal, if any, being forced out and extending from the point of the blank at the same
time. By means of thus shaping the points, the time and attendance necessary to
produce the same result in another machine or operation is avoided. At the termina-
tion of the smooth portion 6', the ribs for forming the threads on the points commenco.
These thread-forming ribs and grooves are practically the prolongation of those which
form the screw-threads on the body of the screw. It will be observed, referring to
Figs. 1 and 12, that a portion of the said ribs, a, and grooves b, terminate along the
upper edge of the plain or point-shaping portion b¹.
Fig. 10 represents, in plan, a machine adapted to produce a scrow having an
automatically shaped and screw-threaded point p³, (Fig. 9). Said machine represents
one of the dies A, secured to the framing B, while the other die is oppositely mounted
in guides g, and adapted to reciprocate back and forth in front of the stationary die
by means of a connecting rod d, crank C, and revolving shaft m. t indicates an
inclined trough or run-way," adapted to conduct blanks (Fig. 5) to the dies,
while the latter are normally separated, as at the end of the stroke. It is obvious
that the dies may be mounted so that both are adapted to travel, in which case the
screw will not advanco but simply turn on its axis while being submitted to the action
of the dies.
The operation is as follows:-
A blank, s, roughly pointed, as at p, f, (Figs. 5 and 6) and having a plain shank 8,
terminating at its upper end in a head h, (nicked, as at n, if desired) is placed in a
vertical position at the left of the stationary die A. Now, by suitable connections the
movable die is forced ahead toward the right. (See arrow-direction). The dies being
so adjusted relatively to each other, that the blank is grasped between them at the
same instant from opposite sides. The screw is carried along between the dies (by
the action of the movable one) until it passes the rear end of the stationary die, when
the screw drops from them through an opening ', which conducts it to a receptacle
beneath. At the commencement of the operation the ribs a, are forced into the
metal of the shank s, and as the rolling progresses to form the thread the lower
portion, of the dies at the same time transforms the roughened point p into an
elongated and symmetrical point p² (Fig. 7). The further movement of the die as it
carries the screw past the end of the plain portion 6', producing a continuation of the
screw-thread t, from the shank to the end of the screw. The final action of the dies
produces a completely threaded screw, E, substantially as represented in Fig. 9. In
Figs. 12 and 13 the rear portion of the stationary die is provided on its under side
with a short cutter, 63, which, co-operating with the sharpened edge 6, of the movable
die, (Fig. 13) serves to shear off any superfluous metal or burr, as 66, Fig. 14, from
the lower end of the screw that may be produced during the rolling process.
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 Í
claim is :-
1. Grooved dies for rolling the threads on screws, each die having a portion of its
working face formed to first reduce and elongate the point portion of the screw-blank
o a symmetrical shape by an ungrooved beveled surface and then to roll a screw-
hread on said point, the latter thread being a continuation of that simultaneously
produced on the body of the screw.
2. The combination, in a screw-threading machine, of two grooved dies, one of
which may be stationary, for rolling the threads on screws, each die having a portion
f its beveled working face ungrooved, to reduce the point of the screw-blank to
symmetrical shape, and then by means of ribs and grooves formed in the

page_text: succeeding portion of the said beveled surface, to roll a screw-thread on the point of
the screw.
3. The combination, of a pair of thread-forming dies, each having a beveled
portion of its working face, longitudinally, ungrooved to first shape the point of the
blank and then by means of grooves formed in the continuation of said ungrooved
portion to roll a screw-thread thereon; and a cutting edge adapted to sever superfluous
metal from the tip of the screw.
Dated this 25th day of November 1887