IMPROVEMENTS IN MACHINERY FOR MANUFACTURING SCREWS."
Year: 1878

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
<
& Co., Patent Agents, Southampton Buildings, London, for the Invention
of IMPROVEMENTS IN MACHINERY FOR MANUFACTURING SCREWS." A com-
munication from abroad by Charles Dake Rogers, of Providence, Rhode
Island, United States of America.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 1st August 1878.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN MACHINERY FOR MANU-
FACTURING SCREWS." A communication from abroad by Charles Dake Rogers
of Providence, Rhode Island, United States of America.
My Invention relates to improvements in machines for making fine thread or
"machine" screws, and consists in combining with the screw cutting or threading
dies a milling or other cutting tool for contemporaneously dressing the end of the
blank during the performance of the operation of threading the same, such end
dressing tool being so arranged that it may have a retrograde movement relatively
to the threading dies, in case the pitch of the said dies acting as a leader for the end
dressing tool would otherwise cause a too rank cut to be made.
It will be readily understood that metal or "machine" screws; with rounded or
pointed ends, are extremely desirable, as they can conveniently and without loss of
time be made to take the lead of the thread, and that such ends will present a
finished appearance should they come to view.
Heretofore the operation of rounding or pointing the ends of such screws has been
performed by machinery, independently of and entirely distinct from the machines
which thread them, necessitating not only an expenditure for the construction and
maintenance of the former machinery, but also for attendance thereon. This
division of labor between two sets of machines has also necessitated an expense for

page_text: attendants to transport the screw blanks from the pointing to the threading
machines has required twice the amount of lubricant to be used in the operations of
pointing and threading as would be used if both operations were performed by one
machine, and has also necessitated the keeping in stock of two complete sets of
blanks, amounting in large establishments to many tons of manipulated metal.
Now the object of this Invention is to provide a threading machine with a device
which shall round or point the end of a screw contemporaneously with the operation
of the threading dies upon the said screw, thereby saving the cost of and attendance
upon a separate set of pointing machinery, and the time necessary to perform the
operation of pointing by said machinery saving fifty per cent. of the oil heretofore
necessary to be used, and one handling of the blanks, and decreasing by fifty per
cent. the stock of blanks heretofore required to be kept in stock.
In the threading of a screw blank, as usually performed, either the said blank is
griped by jaws, which after it is in place are revolved, and the said blank is made
to approach or be approached' by non-revolving dies, or the blank is griped by non-
revolving jaws and made to approach or be approached by revolving dies.
This Invention is applicable to either class of machines, which are so well known
as to need no description, therefore only the said die holder and its parts will herein-
after be considered, they being the only mechanism necessary to the understanding
of my Invention
•
Figure 1 represents in longitudinal section the die holder spindle, containing the
said improved device for rounding or pointing the end of a screw.
Figure 2 is an end view of the said spindle, with its head removed showing the
cutter in place; and Figures 3 and 4 are views of finished screws, the former with
a rounded and the latter with a pointed end.
Like letters indicate the same parts throughout the Drawing,
As shown in Figure 1, A represents the hollow die-holder spindle, the same being
furnished with a head as at A', in and to which the dies B are secured. Mounted
in the same spindle òr arbor is a cutter as at C, having one or more operating faces,
the said cutter being splined to the spindle A to prevent rotary motion upon its own
axis. As above stated the operation of dressing the end of the screw takes place
contemporaneously with the threading, it being performed during the completion of
the thread.
The force by which the dressing is done is furnished by the "lead" of the screw,
and it is obvious that if the cutter be stationary, that is, without arrangement for
retrograde motion, the said lead may be too great for the cutter to properly perform
its function. It is therefore desirable that the cutter while doing its work be held
in contact with the end of the screw by a yielding pressure, so that it may gradually
retire with the advancement of the screw in order that its cut may not be too
For this
'rank," and that the end may be properly dressed the required amount.
purpose it is seated upon a stiff spiral spring as at D, constituting a yielding seat,
the said spring being in turn seated upon a spindle as at E, which is preferably
splined to the spindle A.
As screws of various lengths are cut or threaded upon one and the same machine
it is necessary that means should be provided by which the cutter may be longi-
tudinally adjusted with reference to the dies to properly receive and operate upon
the ends of the screws. For this purpose the spindle E is tapped to engage with a
screw as at F, having a collar f upon its head, and the end of the spindle A is fur-
nished with a flanged nut as at G, which works upon the said spindle and operates
by clamping the collar f to the end of the spindle A, to hold the spindle E, spring D,
and cutter C in proper longitudinal position after the adjustment has been made by
the screw F, and secure the parts, which will then be ready for service.
The operation of the said device is as follows:-It being desired to thread and
point screws of a definite length proper arrangements are first made for threading

page_text: the required length of the shank, then the cutter C is longitudinally adjusted with
reference to the dies B by means of the screw F, so that before the thread is com-
pleted the said cutter shall act upon the end of the screw a sufficient length of time
to properly dress it. The threading then commences, but before its completion the
end of the screw comes in contact with the cutter C, which during the finishing of
the thread dresses the end into the desired shape, so that when the screw is dis-
charged its shank is threaded and its point shaved, as shewn in Figures 3 or 4 of
the Drawing.
Having thus fully described the said Invention, as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I do not limit myself to the precise construction shewn and described, as the
same may be varied without departing from the spirit of my Invention, as for
instance in place of obtaining a yielding pressure upon the cutter by means of a
spiral spring, another form of spring may be used; or a positive retrograde motion
may be given to the said cutter, the said motion being relatively proportional to
the lead of the screw, and the object sought to be accomplished. I am also aware
that the threading may be performed by non-revolving dies or a threading tool
during the operation of which a side tool exerting a yielding pressure or having a
retrograde motion proportional to the leal of the screw, could be made to dress
the end of the screw, such a construction, however, would be within the scope of my
Invention, and I further wish it understood that I claim,-
First. In a screw cutting or threading machine, the combination of a die or tool
for cutting or threading the blank, and a tool for contemporaneously pointing or
dressing the end of the said blank when such pointing tool is arranged to have a
retrograde movement relatively to the threading tool, as above described.
Second. In a screw cutting or threading machine the combination with the
threading die or tool of a cutter and mechanism for longitudinally adjusting it with
reference to the said threading tool, the said cutter being arranged to have a retro-
grade movement relatively to the threading tool, and operating to dress the end of
a screw blank contemporaneously with the threading of the same, as herein
described.
Third. In a screw cutting or threading machine the combination of a threading
die and a pointing or end-dressing tool mounted in an arbor common to both, and
so arranged that the thread in process of cutting by the dies can act with the dies
as the "leading-on" screw for the pointing tool, as above described and shown, and
for the purposes specified.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this First day of August, in the year of our Lord One
thousand eight hundred and seventy-eight.
WM. ROBT. LAKE. (L.S.)