IMPROVEMENTS IN SCREW CUTTING AND THREADING MACHINES, AND IN THE CONSTRUCTION OF SCREW NAILS AND SPIKES
Year: 1866

page_text: LETTERS PATENT to Charles Douglas Fox, of New Street, Spring Gardens,
in the County of Middlesex, Member of the Institute of Civil Engineers,
for the Invention of "IMPROVEMENTS IN SCREW CUTTING AND THREADING
MACHINES, AND IN THE CONSTRUCTION OF SCREW NAILS AND SPIKES."-A
communication from abroad by John Howard, residing at New York,
in the United States of America.
Sealed the 26th October 1866, and dated the 30th April 1866.
PROVISIONAL SPECIFICATION left by the said Charles Douglas Fox at the
Office of the Commissioners of Patents, with his Petition, on the 80th
April 1866.
I, CHARLES DOUGLAS Fox, of New Street, Spring Gardens, in the County of
Middlesex, Member of the Institute of Civil Engineers, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN SCREW CUTTING AND
THREADING MACHINES, AND IN THE CONSTRUCTION OF SCREW NAILS AND SPIKES," &
communication to me from abroad by John Howard, resident at New York,
in the United States of America, to be as follows:-
This Invention relates, firstly, to certain improvements in machines for
cutting and threading screws; and, secondly, to an improvement in the con-
struction of screw nails and spikes, whereby they may be turned into the wood
by driving, and withdrawn by means of a turn-screw without injuring the
head of the screw by driving, and without breaking the wood, which would

page_text: prevent the proper application of the turnscrew, and the formation of a com-
pact counterṣcrew for the threads of the screw nail or spike to turn in.
The first improvement consists in the use and application of a ratchet
and catch attached to the inside of the friction pulley of the machine,
which is set on the driving shaft; this ratchet contains teeth or notches in
its edge equal in number to the number of threads desired to be cut in the
screw blank, and is held in place by the catch. The pin by which the catch
is operated projects through a slot in the side of the friction pulley, and strikes
upon an incline, throwing the catch out of the tooth or notch in the ratchet,
allowing the ratchet and the part of the friction pulley to which it is attached
10 revolve the fraction of a revolution until the catch falls into the next tooth
pr notch in the ratchet. This incline slides upon a way attached to the frame
of the machine and is moved to its place, so that the pin will strike upon it
at the proper time by a cam attached to the back shaft of the machine, and is
thrown out of the way when not needed by a spiral spring. When the
ratchet and the part of the friction pulley to which it is attached revolves the
fraction of a revolution the spindle to which they are fastened also revolves
the same fraction of a revolution. This spindle carries the screw blank, upon
which the threads are to be cut, and when one thread has been cut the pin
strikes upon the incline, releasing the catch, which allows the ratchet and
the spindle to revolve a fraction of a revolution, carrying the screw blank
with them the same fraction of a revolution, so that a second thread can be
ut upon the blank. The ratchet has three teeth or notches, which permit
three threads to be cut upon the screw blank, but the number may be
increased by increasing the number of teeth or notches in the ratchet.
The second improvement consists in the use of spiral springs in the hub of
the main pulley. These springs act against a friction plate connected to the
pulley by bolts, and press it against a collar, which regulates the pressure of
a pair of jaws upon the screw blank, thereby adjusting the pressure, so that
blanks slightly varying in size shall be firmly held while the threads are being
cut upon them.
The third improvement consists in the construction of the "firmer," which
is made hollow and slipped upon a rod fastened to the "firmer" plate and
secured in position by a screw. The exterior surface of the firmer is turned
up in a lathe, so that it shall conform to the exterior surface of the desired
pointed screw blank throughout the line of contact when they are placed
together side by side, so that the point of the screw blank shall just lie in the
same plane with the base of the conical part of the firmer..
The fourth improvement consists in the method of attaching the firmer to

page_text: the firmer plate by slipping it upon the rod and fastening it with a set screw,
so that when it becomes worn in any part it can be turned round on the rod
to bring a portion of the surface not worn nearest the screw blank, and also
making it adjustable to screw blanks of different lengths by moving it on the
rod in the direction of its length and fastening it with the set screw.
The fifth improvement consists in hanging the firmer plate upon a
centre screw, and securing it in the requisite position by set screws, so
that threads may be cut upon a cylindrical or a taper blank, as may be desired.
The sixth improvement consists in the application of a bent revolving fork,
by which the screw blanks are picked up out of a hopper and placed upon a
track, by which they are conducted to the screw-threading device. This fork
is so bent that in revolving the pointed ends of the two tines pass both on one
side of the track, and the other ends of the same tines come just even with
and slightly touch against the corresponding rails of the track. This fork
has an intermittent motion, coming to a full stop at each revolution, so as
to allow the blanks picked up during that revolution to run off upon the track.
The seventh improvement consists in the use of bevil gearing, by which
motion is communicated to the fork; one of these has a portion of its cogs
cut away, leaving just enough to cause one complete revolution of the fork.
This allows the fork, after it has made one complete revolution, to come to. a
full stop, while the bevil gear wheel travels over the vacant space in the bevil
gear wheel.
The eighth improvement consists of a graduated cam, the revolution of
which moves a bar in the direction of its length by forcing a pin projecting
from a shoulder on the bar up the inclined side of each of the successive
steps or gradations of the cam, and when the pin has been carried over the
last step or gradation of the cam it is brought suddenly back to the position
it first occupies by. the action of a spiral spring contained within the hollow
shaft of the cam pressing against a nut upon the inner end of the bar. The
bar, when moved by the graduated cam, operates the device, by which the
depth of each cut is determined in forming each thread upon the screw blank,
and the cam has as many steps or gradations as it requires cuts to form the
desired thread. The cam has also an intermittent motion moving a fraction
of a revolution at a time, and intermitting when the pin is upon the plane of
each step or
gradation as many times as there are threads to be cut upon
the screw blank, so that if there are three threads to be cut upon each
blank and it requires three cuts to form each thread, the cam is so
constructed and operated that when the pin forced upon the first step or
gradation of the cam one cut will be taken from the first thread on the blank;
-":

page_text: the cam then moves the fraction of a revolution and stops, and one cut is
taken from the second thread on the blank; the cam then moves the fraction
of a revolution farther and stops, and one cut is taken from the third thread
on the blank; the cam then moves a fraction of a revolution further and
stops, and the pin is forced upon the second step or gradation of the cam,
and the second cut is taken from the first thread on the blank, and so on in a
similar manner the cam moves and stops till three cuts have been taken
from each of the three threads upon the blank.
The ninth improvement consists in a device for pointing a screw blank
when held in the jaws of the revolving spindle, and at the same time steadying
the screw blank in its place while it is being pointed. The point outter is
attached to the inner end of the sliding bar. The cutter is set so that its
edge will project a little throughout the whole of one of the sides of a conical
hole, so that when the pointer is brought up to the blank by the action of the
sliding bar the centre of the conical hole containing the cutter will be in a
direct line with the centre line of the spindle, and while the cutter is pointing
the blank the blank will be sustained in its place by the other parts of the conical
hole. The action of this point cutter upon the blank is similar to that of the
fommon lead pencil sharpener upon a common wooden pencil. The point
cutter is brought up to its proper place for pointing the blank at the proper
time by a cam, and when the blank is pointed is thrown by the same oam out
of the way of the threading tool.
making the threading
The mode of accom-
which the end of the
The tenth improvement consists in the mode of
tool post adjustable to blanks of different lengths.
plishing this is by the application of a bushing, in
shaft runs; a nut is fastened to the inside of the shaft of the tool post by a
screw; a rod threaded at one end works in the nut, and at the other end
enters the bushing, where it is made to turn with the bushing by means of a
feather sliding in a groove in the bushing, the end of the rod coming in contact
with the end of the lower or feeding shaft. It will readily be understood that
when the bushing is turned in either direction the rod will be screwed into or
out of the nut, which being fastened to the tool post will carry the tool post
with it in the same direction, and thus be made adjustable to blanks of different
lengths.
The last improvement relates to the construction of the screw nails or spikes
by forming the inclination of the threads of an angle so acute that they will
penetrate the wood freely by a percussive action, and at the same time not so
acute as to prevent them from being turned out by a screw driver. The angle
of the thread is usually so oblique to the axis of the nail that it requires several

page_text: threads to cover the shank, in the present example five, each of which forms
a helix of a quarter of an inch exterior diameter; with one turn of the thread
every three quarters of an inch. The outline of the upper face of the thread
in its radial cross section is a straight line and at right angles to the axis of
the shank, but the under side of the thread forms a very oblique angle
with the axis, and it is curved so as to leave a large space between the threads
of the nail, which being of metal are comparatively strong, that the wooden
thread into which they are turned and which is of comparatively weak
material may be as large as possible. This curvature leaves the inclination of
the under side of the thread such as will allow it to penetrate the wood freely
when driven. I remove the corners of the nick on the head of the screw, so
that the blows of the driving hammer will fall upon the middle of the part on
each side of the nick, which may be battered to any extent required in driving.
it into the hardest wood without in any way obstructing the nick or the
application of a turnscrew:
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Douglas Fox in the Great Seal Patent Office on the
30th October 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DOUGLAS Fox, of New Street, Spring Gardens; in the County of Middlesex
Member of the Institute of Civil Engineers, send greeting: -
WHEREAS Her most Excellent Majesty Queen Victoria; by Her Letters
Patent, bearing date the Thirtieth day of April, in the year of our Lord One
thousand eight hundred and sixty-six, in the twenty-ninth year of Her reign,
did; for Herself; Her heirs and successors, give and grant unto the said
Charles Douglas Fox, Her special licence that I, the said Charles Douglas
Fox, my executors, administrators, and assigns; or such others as I, the said
Charles Douglas Fox, my executors; administrators, and assigns, should at
any time agree with, and no others, from time to time, and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland; the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN SCREW CUTTING AND THREADING MACHINES; AND IN THE CON-
STRUCTION OF SCREW NAILS AND SPIKES," a communication to me from abroad by
John Howard, resident at New York, in the United States of America, upon the
condition (amongst others) that I, the said Charles Douglas Fox; my executors

page_text: or administrators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of the said.
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
· NOW KNOW YE, that I, the said Charles Douglas Fox, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
.
This Invention relates, firstly, to certain improvements in machines for
cutting and threading screws; and, secondly, to an improvement in the con
struction of screw nails and spikes, whereby they may be turned into the
wood by driving, and withdrawn by means of a turnscrew without injuring
the head of the screw by driving, and without breaking the wood which
would prevent the proper application of the turnscrew and the formation of a
compact counter screw for the threads of the screw nail or spike to turn in.
In the accompanying Drawings Fig. 1 represents a front view; Fig. 2 the
end view; and Fig. 3 the top view of the screw-cutting and threading machine
with my improvements applied; the remaining Figures represent the
improvements invented by me in detail which will be hereafter explained in
this description.
My first improvement consists in the use of a ratchet and catch attached
to the inside of the friction pulley, marked A, Fig. 1, upon the spindle marked
L, Fig. 1, and which is more fully shewn in Fig. 9, in which E represents the
ratchet wheel; C the catch; F, the end of the pin operating the catch; B,
the incline, against which the pin F strikes as the friction pulley A revolves.
This ratchet E, Fig. 9, contains teeth or notches in its edge equal in number
to the number of threads desired to be cut in the screw blank, and is held in
place by the catch C. The pin F by which the catch C is operated projects
through a slot in the side of the friction pulley A, not shewn in the Figure,
and strikes upon the incline B, throwing the catch out of the tooth or notch
in the ratchet, allowing the ratchet and the part of the friction pulley to which
it is attached to revolve the fraction of a revolution until the catch falls into the
next tooth or notch in the ratchet. This incline B, Fig. 9, is of peculiar shape
and slides upon a way, marked M, attached to the frame of the machine, and
is moved to its place so that the pin will strike upon it at the proper time by
a cam, marked H, attached to the back shaft of the machine, and is thrown
out of the way when not needed by the spiral spring marked G. When the
ratchet and the part of the friction pulley to which it is attached revolves the

page_text: friction of a revolution the spindle L, Fig. 1, to which they are fastened also
revolves the same fraction of a revolution. This spindle carries the screw
blank upon which the threads are to be cut, and when one thread has been
cut the pin F, Fig. 9, strikes upon the incline B, releasing the catch C, which
allows the ratchet E and the spindle to revolve a fraction of a revolution,
carrying the screw blank with them the same fraction of a revolution, so that
a second thread can be cut upon the blank. In Fig. 9 the ratchet E has
three teeth or notches, which permit three notches to be cut upon the screw.
blank, but the number may be increased by increasing the number of teeth
or notches in the ratchet. In Fig. 12 the spindle L and the jaws in which
the screw blanks are held are shewn in section, in which Fig. A represents
the friction pulley without the ratchet and catch.
My second improvement consists in the use of spiral springs in the hub of
the main pulley marked I, Fig. 1, and more clearly shewn in Fig. 12, where
a section of the same pulley is given also marked I, and the spiral springs are
shewn marked K. These springs act against a friction plate marked J, con-
nected to the pulley I by bolts, and press it against the device marked O that
regulates the pressure of the jaws marked P, P, upon the screw blank;
thereby adjusting the pressure so that blanks slightly varying in size shall be
firmly held while the threads are being cut upon them.
My third improvement consists in the construction of the firmier marked Q,
Fig. 4, which is made hollow and slipped upon the rod R fastened to the
firmer plate S, and secured in position by a screw. The exterior surface of
the firmer Q is turned up in a lathe, so that it shall conform to the exterior
surface of the desired pointed screw blank throughout the line of contact.
when they are placed together side by side, so that the point of the screw
blank shall just be in the same plane with the base of the conical part of the
firmer.
'
My fourth improvement consists in the method of attaching the firmer to
the firmer plate S, Fig. 4, by slipping it upon the rod R, and fastening it with
a set screw, so that when it becomes worn in any part it can be turned round
on the rod R to bring a portion of the surface not worn nearest the screw.
blank, and also making it adjustable to screw blanks of different lengths by
moving it on the rod R in the direction of its length and fastening it with
the set screw.
My fifth improvement consists in hanging the firmer plate S, Fig. 4, upon
a centre screw, marked V, and securing it in the requisite position by the set
screws marked T, T, so that threads may be cut upon a cylindrical or a taper
blank as may be desired. The situation of the firmer plate and its attachments
:

page_text: is shewn in Fig. 3, marked S; Fig. 5 represents a sectional view of the firmer
plate and its attachments.
My sixth improvements consists in the bent revolving fork, marked W in
Figs. 6 and 7, by which the screw blanks are picked up out of the hopper Y,
and placed upon the track marked X, by which they are conducted to the
screw-threading device not shewn in these Figures. This fork W, Fig. 7, is
so bent that in revolving the pointed ends of the two tines pass both on one
side of the track X, X, and the other ends of the same tines come just even
with and slightly touch against the corresponding rails of the track, in which
position they are shewn in Fig. 7. This fork W, Fig. 6, has an intermittent
motion coming to a full stop at each revolution, so as to allow the blanks
picked up during that revolution to run off upon the track X; they will do
this when the fork W is in the position shewn in Fig. 6.
My seventh improvement consists in the use of the bevil gearing marked
U and Z, Fig. 7, by which motion is communicated to the fork W. One of
these has a portion of its cogs cut away, leaving just enough to cause one
complete revolution of the fork W, as shewn in Z. This allows the fork W
after it has made one complete revolution to come to a full stop, while the
bevil gear wheel W travels over the vacant space marked Z' in the bevil gear
wheel marked Z.
My eighth improvement consists in a graduated cam marked a, Fig. 3, of
which a longitudinal section is shown in Fig. 11. This graduated cam in
revolving moves the bar 6 in direction of its length, by forcing a pin projecting
from the shoulder of the bar b, Fig. 3, as shewn at c, Fig. 3, up the inclined
side of each of the successive steps or gradations of the cam a, and when the
pin c, Fig. 3, has been carried over the last step a gradation of the cam a it
is brought suddenly back to the position it occupies in Fig. 3, by the action
of the spiral spring marked a, Fig. 11, contained within the hollow shaft of
the cam a, pressing against a nut upon the inner end of the bar b, Fig 11.
The bar b, Fig. 3, when moved by the graduated cam a operates the device
by which the depth of each cut is determined in forming each thread upon
the screw blank, and the cam a has as many steps or gradations as it requires
cuts to form the desired thread. The cam a has also an intermittent motion
moving a fraction of a revolution at a time, and intermitting when the pin c is
upon the plane of each step or gradation as many times as there are threads
to be cut upon the screw blank, so that if there are three threads to be cut
upon each blank, and it requires three cuts to form each thread, the cam a is
so constructed and operated that when the pin c is forced upon the first step
or gradation of the cam a one cut will be taken from the first thread on the

page_text: blank; the cam a then moves the fraction of a revolution and stops, and one
cut is taken from the second thread on the blank; the cam a then moves the
fraction of a revolution further and stops, and one cut is taken from the third
thread on the blank; the cam a then moves a fraction of a revolution further
and stops, and the pin c is forced upon the second step or gradation of the
cam a, and the second cut is taken from the first thread on the blank, and
so on in a similar manner; the cam a moves and stops till three cuts have
been taken from each of the three threads upon the blank.
My ninth improvement consists in a device for pointing a screw blank when
held in the jaws P, P, Fig 12, of the revolving spindle L, and at the same
time steadying the screw blank in its place while it is being pointed. The
point cutter is attached to the inner end of the sliding bar e, Fig. 3, and
is shown in detail in Fig. 8, in which a represents a side view, and k an end
view thereof. The cutter is set so that its edge, marked i, Fig. 8, will project
a little throughout the whole of one of the sides of a conical hole shown at 2,
so that when the pointer is brought up to the blank by the action of the
sliding bare the centre of the conical hole containing the cutter will be in
a direct line with the centre line of the spindle L, Fig. 1, and while the cutter
is pointing the blank the blank will be sustained in its place by the other
parts of the conical hole. The action of this point cutter upon the blank is
similar to that of the common lead pencil sharpener upon a common wooden
pencil. The point cutter is brought up to its proper place for pointing the
blank at the proper time by a cam not shewn in the Figures, and when the
blank is pointed is thrown by the same cam out of the way of the threading tool.
My tenth improvement consists in the mode of making the threading tool
post in Fig. 1 adjustable to blanks of different lengths. The mode of
accomplishing this is shewn in detail in Fig. 10, in which a sectional view is
given of the parts, m representing the shank of the tool post o, the end of
the lower or feeding shaft, marked o, Fig. 1; n, the bushing in which the
end of the shaft o runs; r, a nut fastened to the inside of the shaft of the tool
post by a screw; and p, a rod threaded at one end working in the nut r, and
at the other end entering the bushing where it is made to turn with the
bushing by means of the fly a sliding in a groove in the bushing, the end of
the rod p coming in contact with the end of the lower or feeding shaft o, as
shewn in Fig. 10. It will readily be seen that when the bushing n, Fig.
10, is turned in either direction the rod p will be screwed into or out of the
nut r, which being fastened to the tool post m will carry the tool post with it
in the same direction, and then be made adjustable to blanks of different
lengths.
.

page_text: The next part of my Invention relates to the construction of a spike or nail
in such manner that it may be turned into the wood by driving and out by
means of a turn screw without having its head bruised by the driving, so as
to prevent the proper application of the turnscrew, and without breaking the
wood by the driving so as to prevent it from forming a good and compact counter
screw for the threads of the nail to turn in. The inclination of the threads
of a screw like this must be such that the angle will be sufficiently acute to
cause it to penetrate the wood freely, and at the same time not so acute as
to prevent it from being turned out by a screwdriver, a very good angle is
that shewn in the Drawing, where Fig. 13. represents a side elevation; Fig.
14, a longitudinal section of one of my screw spikes; Fig. 15, a plan of the
head; and Fig. 16, a horizontal section at the line X, X. The angle of the
thread is usually so oblique to the axis of the nail that it requires several
threads to cover the shank, in the present example five, each of which forms
a helix of a quarter of an inch exterior diameter with one turn of the thread
every three quarters of an inch. The outline of the upper face (14) of the
thread (a) in its radial cross section is a straight line, and at right
angles to the axis of the shank, but the under side of the thread forms a very
oblique angle with the axis, and it is curved so as to leave a large space
between the threads of the nail which being of metal are comparatively strong,
that the wooden thread into which they are turned and which is of com-
paratively weak material may be as large as possible. The curvature leaves
the inclination of the under side of the thread such as will allow it to penetrate
the wood freely when driven. If the nick of the head were of the usual form
with its corners on a level with the crown of the head the blows of the
instrument employed for driving it would batter it so that it would be wholly
or partially closed, which would prevent the entrance of the blade of the
screwdriver to turn it out. To obviate this difficulty I remove the corners
(e) of the nick, so that the blows of the driving hammer will fall upon the
middle of the part on each side of the nick which may be battered to any extent
required in driving it into the hardest wood without in any way obstructing
the nick or the application of a turn screw. The mainfold modifications
which may
be made in the screw nail and spike, without in any way departing
from the principle of my Invention are obvious, and therefore I will not describe
them, and so the uses and advantages of the article are also too obvious to
require specification.
I claim, firstly, the improvements in screw cutting and threading machines.
Secondly, the construction of screw nails or spikes with a thread shaped as
described.

page_text: And, thirdly, the shaping of the head so that the battering caused by the
driving will not obstruct the application of the turnscrew, substantially as
herein specified.
In witness whereof, I, the said Charles Douglas Fox, have hereunto
set my hand and seal, this Thirtieth day of October, in the year of
our Lord One thousand eight hundred and sixty-six.
CHARLES DOUGLAS FOX. (L.S.)
Witness,
J. C. H. SIEVIER,
Clerk to Messrs. Prince & Co.,
4, Trafalgar Square,
Charing Cross.