Improvements in Tool Box for Screw Cutting. Lathe
Year: 1885

page_text: Improvements in Tool Box for Screw Cutting. Lathe.
JAMES SHAW, THORNTON HARRISON and WILLIAM SHAW, Engineers 50 Lyndhurst
Street Leeds Road Bradford do hereby declare the nature of our invention for
IMPROVEMENTS IN TOOL BOX FOR SCREW CUTTING LATHE to be as follows:-
A motion that allows the cutting tool of lathe to regulate itself to any angle
during the process of cutting positive gaining screws, by means of a conical
spindle working in the tool box, with steel cutter attached to one end, and to the
other end is attached a lever or crank working on an inclined plane, which incline
has to be regulated (before starting to cut a gaining screw) by means of screws, so
as to give the angle required.
JAMES SHAW..
THORNTON HARRISON.
WILLIAM SHAW.
We, JAMES SHAW, THORNTON HARRISON, and WILLIAM SHAW all of 50 Lyndhurst
Street, Leeds Road, Bradford in the County of York, Engineers, do hereby declare
the nature of our invention for IMPROVEMENTS IN TOOL BOX FOR SCREW CUTTING
LATHE and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
This invention relates to an improved tool box applicable to lathes for cutting
differential screws and for other purposes when the angle of relief, that is the
angle formed by the face or faces of the cutter and the work operated upon is
subject to variation; by our improvements the tool or cutter is automatically
Prion 1

page_text: altered, and regulated so that the same angle of relief is maintained with the
varying inclination of the thread of a differential screw throughout the wholo
process of cutting such screw.
To carry out our invention we employ a tool holder of circular section mounted
in suitable bearings formed in the tool box and fitted with a lever at right angles
thereto, a stud projecting from the end of such lever rests in an adjustable guide,
set at an angle with the lathe bed, thus as the tool box is traversed along the
lathe the inclined guide slightly turns the tool holder on its axis, thus altering
the inclination of the cutter held thereby to correspond to the varying inclination
of the thread of the differential screw, thereby maintaining a correct angle of relief
whilst cutting such screw.
Reference is to be had to the accompanying drawings forming part of this
- specification, in which similar letters of reference indicate corresponding parts in
both of the figures. Figure 1 is an elevation of an ordinary screw cutting lathe
shewing our improved tool box and apparatus connected therewith Figure 2 is a
plan of the same.
The tool holder A rests in conical bearings formed in the tool box B, a lever C is
fitted to the end of the tool holder and the stud D projecting therefrom slides in
the inclined guide E such guide being supported by the brackets F and its
inclination with the lathe gautre G is regulated by the screws H thus the
inclination of the cutter J held by the tool holder A is automatically altered as the
tool box traverses the lathe gautre G according to the inclination of the guide E
with such gautre.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare what we
claim is
Automatically regulating the angle of relief of the cutter in lathes for cutting
differential screw-threads, and analogous purposes, substantially as herein shew
and described.