An Improved Screw for Woodwork and other purpose 3.
Year: 1893

page_text: Date of Application, 18th July, 1893
Complete Specification Left, 20th Oct., 1893-Accepted, 25th Nov., 1893
PROVISIONAL SPECIFICATION.
An Improved Screw for Woodwork and other purpose 3.
I, GEORGE AUGUSTUS MACNUTT of Collins Street, Melbourne in the Colony
of Victoria, Doctor of Medicine, do hereby declare the nature of this invention to
be as follows:-
This invention has been devised for the purpose of providing the public with an
improved screw for use in connection with wood work and other materials for which
analogous screws are at present used.
My invention may be described as follows.-Instead of the usual tapering shank
and spiral thread which coils around same and terminates at a point, I form my
improved screw by cutting the thread out of the solid shank in such a manner that
the metal below the edge of the thread is formed so as to concavely taper into the
top of the next lower thread. The top surface of the depth of each thread is as
nearly as possible rectangular to the general plane of the screw thread, and an
elevation of the screwed part presents a view of a series of vertical steps from the
inside of each of which said steps the metal extends upwardly and concavely to the
edge of the next thread above.
The pointing of my screw is effected by tapering the hereinbefore described
thread as it approaches the termination and finally it resolves itself into a point.
Dated th: 10th 1... T... 1909
G. A. MACNUTT.
W. H. Beck,
Per S. E. Gunyon,
115, Cannon Street, London, Agent.
COMPLETE SPECIFICATION.
An Improved Screw for Woodwork and other purposes.
I, GEORGE AUGUSTUS MACNUTT of No. 24 Collins Street, Melbourne, in the
Colony of Victoria, Doctor of Medicine, 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 has been devised for the purpose of providing the public with an
improved screw for use in connection with wood work and other materials, and
which, by its peculiar form, is calculated to offer increased facilities and advantages
over such screws as are at present in use.
My invention may be described as follows :-In lieu of the usual tapering shank
and spiral thread which coils around the same, in ordinary screws, I form my
improved screw by cutting the thread out of the solid shank, and in such a manner
that the metal below the edge of the thread is formed so as to concavely taper into
the top of the next and lower thread, the curve of concavity being variable to suit
the peculiarities of the work intended for the screw to perform.
The top surface of each thread I form with a slightly inward and downward curve,
the angle of declivity of this curve is preferably, but not arbitrarily, seventy-five
degrees from the plane of the screw thread, but such curve may be varied if the
screw is required for any special purpose.
In order that the invention may be the better understood, reference may be made to
the accompanying drawing, in which an illustration is given of my improved screw,
partly in section, and from which it will be seen that the elevation of the screwed
part presents a view of a series of vertical steps, from the inside of each of which

page_text: of the said steps the metal extends upwardly and concavely to the edge of the
next thread above.
In this drawing A represents the remainder of the shank, out of which the screw
thread has been cut, B represents the concave steps, and C the inward curve at the
top of each thread (see section).
The reduced diameter at D shews the manner in which I point my screw, and
which consists in gradually tapering the thread and shank until it reaches the
point.
E represents the ordinary head of a wood screw, with slot for screw driver, but
may be of a square, or other convenient, section to enable a spanner or wrench to
operate same.
I find in practice that my screw will more easily enter woodwork than any
existing screw, and that no pressure, other than the power required to rotate same,
is necessary to cause the thread to penetrate the woodwork.
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―
1. In screws for woodwork and analogous material.-A pointed screw the longi-
tudinal section of which shews that the thread is cut in such a manner that vertical
steps are formed, each of which said steps are concave on their under side and
curving down to the lower step and the top of each step curving inwardly to the
shank at an inclination from the outer edge of the thread, as and for the purposes set
forth and described and in manner illustrated.
2. In screws for woodwork and analogous materials.-A pointed screw the thread
of which comprises a series of steps the top of such steps being formed of a curve,
said curve springing from the shank out to the edge of the thread at such an angle
that the outer point of such curve is at a higher plane than at its junction with the
screw shank, and the under side or rise of such step being formed of a concave curve
leading from the outer point of the curved top down to the inner point of the
next and lower step, as and for the purposes explained and in the manner
illustrated.
Dated this 7th day of September 1893
G. A. MACNUTT.