IMPROVEMENTS IN SCREW-CUTTING TOOLS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Adolphus Selim at the Office of the
Commissioners of Patents on the 10th August 1883. Communicated to him
from abroad by Paul Clement Joseph Lemaire of Rue des Arquebusiers, Paris
in the Republic of France.
ADOLPHUS SELIM of Mincing Lane in the City of London IMPROVEMENTS IN
SCREW-CUTTING TOOLS A communication to me from abroad by Paul Clâment
Joseph Lemaire of Rue des Arquebusiers, Paris in the Republic of France.
Screw-cutting tools constructed according to the present Invention, by their
special construction and arrangement are capable of threading any piece of metal
whether straight, curved or circular and in any given position whether in an
angle or other inconvenient position where the workman, having difficulty in
supporting himself could not work with the ordinary screw-cutting tools, or in a
steam boiler; or a return piece which the workman is obliged to straighten at
the forge to enable it to be threaded by the use of the ordinary screw-cutting
tools, and with the improved screw-cutting tool this work is avoided as the new
tool is capable of threading in any position.
A very important advantage which the present invention possesses, is, that when
any given piece that is not easy or convenient to dismount, has its screw thread
eaten away or injured by rust or by any other action, the improved screw-cutting
tool having dies capable of adjustment at will, the piece can be rethreaded by the
sole action of causing the dies to approach each other by a simple pressure of the
compression ring which enables the dies to be adjusted to the most minute fraction
possible in order to obtain a very clean and correctly cut screw thread, thus
economising a piece which would otherwise require to be replaced by a new piece.
The arrangement of this improved screw-cutting tool is as follows.
Upon a short tube, the upper end of which forms the head of the screw-cutting
tool and which is arranged in such manner as to receive dies of any required screw
thread which are fixed and held in a horizontal groove, are keyed two pincers
each of which is adjusted in a groove provided for this purpose in the longitudinal
part of each side of the head of the screw-cutting tool and which are held at their
axes by a moveable pin which, when this pin is removed and the pincer detached
from the screw cutting tool, enables the dies to be withdrawn from the grooves in
A

page_text: which they are held and other dies of the required character to be put in their
place.
When the dies are replaced in position and the pincers keyed a compressing ring
acts to produce a rigorously exact pressure underneath the lower part of these two
pincers and which by screwing upon its screw thread, forces underneath the lower
part of the pincers and thereby brings the upper part or head of the pincers
against the exterior sides of the dies and by this means determines the complete
adhesion upon the piece of any given metal introduced into the tool to bo
threaded.
The work of thrending is rendered very easy to the operator by the addition of
a key which by being applied to the exterior of the pressure ring facilitates the
regulating without effort then when once the calibre of the thread is regulated the
work of screw-cutting in difficult positions is rendered very easy by the aid of a
-double ended stock of which one arm. is capable of removal such stock acting as a
key and being applied to the lower part of the screw-cutting tool.
Another manifest advantage consists in the arrangement of this screw-cutting
tool which being constructed vertically with an interior passage enables pieces of
even a yard or more in length to be threaded and by means of a circular opening
in the body of the head of the tube coming immediately below the dies it is
rendered casy to ascertain whether the screw thread is being properly made or if
on the contrary the screw thread is badly formed, the workman has only to open
-the-dies-by- screwing-back-the-pressure ring_and_he_can then romove the piece
without involving the loss of time incurred in removing it by screwing back the
|_ Fame.;_then by replacing the head of the piece to be threaded in the dies and by
screwing up the pressure ring acting upon the pincers thie-head is instantly seized--
and the work again proceeds.