An Improved Lapidaries' Tool.
Year: 1890

page_text: Date of Application, 13th June, 1890
Complete Specification Left, 13th Mar., 1891-Accepted, 30th May, 1891
An Improved Lapidaries' Tool.
I, JOHN MESSAZ, of Geneva, in the Republic of Switzerland, Lapidary, do
hereby declare the nature of this invention to be as follows:-
The processes hitherto employed for cutting stones require exceptional skill on
the part of the workman and take a long time to perform. The method of guiding
the nipper carrying the small case or dop which holds the stone to be cut is
especially very imperfect and does not permit of the facets being formed with the
desired regularity.
By my invention I obviate these defects and for this purpose I employ a tool
which can be adapted to any suitable lathe on which is mounted a grinding or
polishing wheel. My improved tool comprises a graduated sector on which slides
a radial carriage carrying in a case the sleeve in which works the rod of the dop
for holding the stone. This case can turn to set the stone at the desired angle
while the position of the carriage on the sector determines the inclination of the
face to be cut. The combination of these two movements allows of the stone being
presented to the wheel in the required direction at the same time causing it to rub
to a greater or less extent by the sliding of the sector parallelwise to the axis of
the lathe.
The sliding carriage can be locked to the sector by means of a jaw.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applican
COMPLETE SPECIFICATION.
An Improved Lapidaries' Tool.
I, JOHN MESSAZ, of Creux de St. Jean Geneva, in the Republic of Switzerland,
Lapidary, 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 :-
The processes hitherto employed for cutting stones require exceptional skill on
the part of the workman and take a long time to perform. The method of guiding
the nipper carrying the small case or dop which holds the stone to be cut is
especially very imperfect and does not permit of the facets being formed with the
desired regularity.
By my invention I obviate these defects and for this purpose I employ a tool
which can be adapted to any suitable lathe on which is mounted a grinding or
polishing wheel. My improved tool comprises a graduated sector on which slides
a radial carriage carrying a sleeve in which is the rod of the dop for holding the
stone. This sleeve can be turned to bring the portion of the stone to be cut into
the desired position while the position of the carriage on the sector determines the
inclination of the facet to be cut. The combination of these two movements allows
The stone is
of the stone being presented to the wheel in the required direction.
at the same time caused to rub against the wheel with more or less pressure by the
sector being adapted to slide parallelwise to the axis of the lathe. The sliding
carriage can be locked to the sector by means of a jaw.

page_text: In order to enable the invention to be fully understood I will describe the same
by reference to the accompanying drawing, in which
Figure 1 is a front elevation partly in section of the improved tool applied to a
lathe
Figure 2 is a plan, and
Figure 3 is an end view partly in section, of the same.
The stone A to be cut is fixed to the end of the rod B which is firmly held in the
sleeve C by a nut E.
The carriage D is fixed to a plate or sole F which can be moved anglewise over
the sector by turning on its pivot H; its position serves to determine the
inclination to be given to the facets of the stone A. and is indicated by an index or
pointer I which it carries laterally and which moves over a graduated scale Jon
the sector G. A lever jaw K serves to lock the sector and the carriage together
and keeps the latter in position when the angle of inclination of the stone with the
wheel M is not required to be altered. The wheel M is mounted in the ordinary
way on the shaft of the lathe by which it is rotated.
The sector G is adapted to slide upon a bar L placed parallel with the shaft of
the lathe, that is to say, perpendicular to the plane of the wheel M. By turning
the sector and consequently the carriage in the direction of the arrow (Figure 3) the
stone is brought in contact with the wheel.
The carriage when its position on the bar L has been regulated is fixed by a set
screw and the pressure of the stone against the wheel is effected by a spring P
the tension of which is regulated by a set screw R which acts at the other end of
the bar of the sector.
In order to cut different facets of the same angle of inclination the rod B and
sleeve C are turned successively to present the stone at the proper angle by
operating a milled knob S carried by the sleeve C. A graduated dial T on the
same axis allows, by means of the spring index U, of the angle to which the facet
is to be cut to be accurately determined which spring index also acts as a stop for
the dial T by taking into notches formed in the periphery of the dial at the end of
cach of the divisions.
The operation is as follows:-
The rod B carrying the stone is first adjusted on the carriage D which is then
slid over the sector G to bring the stone to be cut to the desired angle of inclination
such angle being calculated according to the number of facets to be given to the
polyhedron to be cut. The sector G is slid on its bar L towards the wheel M and
is then turned upward on the said bar in the direction of the arrow f Figure 3 until
the stone rubs against the wheel. When the face has been worn away to the
desired extent the rod carrying the dop is turned in its casing to the proper angle
according to the number of facets to be obtained so as to present the following
face to the wheel and so on.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed declare that what I
claim is
(1.) A lapidaries' tool in which the dop carrying the stone to be cut is mounted
in a sleeve in the interior of a carriage sliding over a graduated sector jointed to
the frame of the lathe carrying the grinding or polishing wheel substantially as
hereinbefore described.
(2.) A lapidaries' tool having a sector mounted on an axis parallel to the axis of
the lathe thereby allowing of an oscillating or rocking movement being given to
the sector in a vertical plane to bring the stone to rub against the wheel sub-
stantially as hereinbefore described.
(3.) A lapidaries' tool in which a carriage is employed having a sliding rotary
movement over a graduated sector and kept in the angular position desired
corresponding to the angle of the facet to be cut by a locking jaw substantially as
hereinbefore described.

page_text: (4.) In a lapidaries' tool the arrangement whereby the rod carrying the dop is
turned in the carriage to set the stone to the desired position which is effected by a
milled knob and an index forming a stop substantially as herein before described.
(5.) The improved lapidaries' tool herein before described and illustrated in the
5 accompanying drawing.
Dated the 13th day of March 1891.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.