METHOD OF MAKING THE HEADS OF WOOD-SCREWS
Year: 1888

page_text: 1 CHARLES DAKE ROGERS, of Providence, in the County of Providence, and State
of Rhode Island, United States of America, Mechanic, do hereby declare the nature.of
my invention for METHOD OF MAKING THE HEADS OF WOOD-SCREWS 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 an improved process in the manufacture of Wood Screws.
In the manufacture of wood screws as heretofore commonly made the heads are
formed by four distinct operations in two separate machines. One of these machines
is called a heading machine, or header, and in it one end of a wire, or bar, which is to
b converted into a screw, is upset or forged in a die to a required form by the action
of the heading hammer, so called, which forces the metal to fill the cavity between
the die and the face of the hammier. Sometimes two haminers are employed, the
first one partially upsetting the metal, but the final form is given mainly by the action
of the second hammer. The face of the second hammer is the counterpart of the face
or end of the head of the screw, with the exception of the slot; a cavity being formed
in it when the face of the screw head is to be round or globular.
The blank with the head thus formed is then taken to another machine in which the
head is shaved to give it the precise shape and size required and a finished surface.
A slot to receive a screw-driver is then, in the same machine, cut by a suitable tool
across the face of the head. After the slot is cut the head is submitted again, in
the same machine, to the shaving operation to remove the burr formed in cutting the
slot. It is obvious that if a finished head can be produced by the use of the heading
machine alone the second machine, that is the shaving and nicking machine, would
not be required and the expense attending its use and the waste of metal would be
avoided. Such waste of metal amounting fully to one-twelfth of the stock required
for a screw.
To secure these results is the object of my inventions herein described.
Machines for operating two heading hammers and the devices for introducing the
wire to the die, holding it against the action of the hammers and removing it from the
die when the upsetting is effected are well known and need not be here described.

page_text: The dies required to form finished heads are those known as solid dies, for the reason
that with open dies, so called, a mark of the line at the junction of the two parts of the
die will show on the surface of the head. The screw heads which will be first referred
to and represented herein are the common conical heads with flat faces and slots in
the faces.
In the drawings, Figure 1 shews a section of a solid die. The conical cavity which
is the counterpart of the conical surface of the screw head to be produced is shown
The wire which is to be upset is represented by b, and the head of the hammer
which is first to act upon it, is represented above it by c.
at a.
In Fig. 2 the same parts are represented after the hammer has been forced down
upon the wire-and die. The upset metal nearly filling the cavity of the die is
represented at d. An unfilled space at the angle of the die and the hammer is shown
at a¹.
In Fig. 3 the same die is reprosented and the wire and completely formed head
by and e. The second hammer head f, differs from the first hammer c, in having
a tongue extending from its face which is the counterpart of and is to produce the
slot in the face of the screw. It and the slot are indicated by the dotted lines y in
Fig. 3.
Fig. 4 is a plan of the end of the wire in the die before it is upset.
Fig. 5 is a plan of the partially formed head and die after the action of the first
hammer, as represented in Fig. 2. In Fig. 6 the face of the completed screw head is
shown, the slot being indicated by h. Fig. 7 is a perspective view of the partially
formed screw head removed from the die represented in Fig. 2, after the action of the
first hammer. Fig. 8 is a perspective view of the completely formed screw head.
Fig. 9 is a perspective view of the second hammer. Fig. 10 is a sectional view of a
die and hammer adapted to produce a rounded head on the end of a screw, the
slot-forming tongue being wholly within the hammer cavity, and Fig. 11 is an inverted
plan view of the hammer showing the cavity and tongue.
It will be observed in Fig. 2 that though the face of the hammer c, is brought down
on to the face of the die there is an unfilled space a', at the angle of the conical
surface of the die with the moulding part of the face of the hammer. This unfilled
space will extend completely around the die as shown in Fig. 5. In Fig. 3 the cavity
of the die is represented as completely filled by the head e. It is obvious therefore
that the unfilled space, a', between the cavity of the die and the face of the hammer
after the action of the first hammer, must be equivalent to the space occupied by the
tongue on the face of the second hammer. It is equally obvious that the amount
of the metal of the wire passed through the die A, for the action of the first hammer c,
must be just sufficient to fill the cavity between the die and the second hammer when
they are in contact. If the amount is not sufficient to fill the cavity the head of the
screw will be imperfect. If it is too great the excess will be forced out between
the opposed faces of the die and the hammer and it will prevent the hammer from
closing upon the die, and will also form a fin around the head which must be
subsequently removed. It will be observed that the first hammer brings the head,
except at the angle of the die and hammer, nearly to the form, with the exception of
the slot, which it is to have finally that is the head has, at the edge, the form of the
conical surface a of the die, and its face has the form with the exception of the slot of
the opposite portion of the face of the hammer, as clearly shown at d, Figs. 2 and 7.
This hammer does therefore the work substantially which has heretofore been done
by the common heading machines. But in addition to this I provide another hammer f
which by means of a tongue g Fig. 9, forms the slot and which also finishes the head
at the angle of the die and the hammer, and by correcting any disturbance of the
face of the head caused by the action of the tongue in entering the metal, finishes the
face of the head and thus gives it the precise shape and size required. It does
therefore substantially the work of the shaving and nicking machine in the old
method of forming heads. In order to do this, however, it is necessary in making
flat heads, as e, which are formed wholly within the cavity of the die, to change the
slot and instead of extending it completely across the head, form it wholly within the
3

page_text: head as shown at h, in Fig. 8. This change not only enables such heads to be formed
by my process but it makes the heads stronger and more homogeneous.
It is not essential that the cavity a in the die should be conical, it may be cylindrical
or globular, or the die may have a flat surface around the hole through which the wire
passes, on which the under surface of the screw head may be formed, as clearly
shown in Fig. 10. In this latter case the cavity m' for giving shape to the head e¹
will be wholly formed in the face of the hammer m.
In making screws with heads having the ends rounded or globular, the cavity as
just stated must be formed in the face of the hammer the counterpart of the surface to
be produced, and if the cavity is of sufficient depth, the tongue g' to form the slot
may be wholly within the cavity and extend completely across it so as to form a slot
on the rounded portion of the head and open at the ends as in similar heads heretofore
made, as shown in said Figs. 10 and 11.
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. The combination of the solid die for forging screw heads with the two punches or
hammers to act in succession for upsetting the metal to form the head, the first of
which has the face which acts on the metal the counterpart substantially, with the
exception of the slot, of the face to be given to the screw head, and the second of
which has its face the counterpart, including the slot, of the final form to be given to
the face of the head of the screw.
2. The method of forming a finished head to a screw by first compressing the metal
between a solid die and a hammer having a working face the counterpart, except as to
the slot, of the end or face to be given to the head of the screw, until it fills the cavity
of the die or of the hammer, or of both with the exception of a space for the
subsequent flow of the metal at the angle between the moulding surface of the
hammer and the moulding surface of the die, and then further compressing the metal
to fill such space by a hammer having its working face the counterpart of the end
or face to be finally given to the head of the screw including the slot.
3. The finishing hammer, substantially as described, baving projecting from its face
a tongue with parallel or nearly parallel sides, to form the slot in the metal within the
cavity of a die in which a flat-faced screw-head is to be formed.
Dated this 4th day of September 1888.
CHARLES DAKE ROGERS,
Inventor.
Hughes, Eli & Hughes,
76, Chancery Lane, London, W.C.,
Agents for the Applicant.