ABOUT MACHINES

Most of the commonly available faceting machines are made in the USA and command a wide range of prices reflecting:-
•the relative constructional simplicity or complexity
•the degree of engineering precision
•the quality of components.
•the inherent degree of consistent accuracy in cutting
The black dial is the angle indicator

Every faceting machine will provide the following as the essential basic facility:-

•an ability to offer the stone to the grinding lap at any precise and consistent angle between 90 and 0 degrees ie from horizontal to vertical.
•an ability to raise and lower the stone by accurate fine adjustment to control precisely the depth of cut or progress of cutting
•an ability to rotate the stone by accurate regular divisions about its axis of rotation, eg a six sided stone needs to divide the complete rotation (360 degees) into six equal units (60 degrees).
•an ability to vary the speed or direction of rotation of the grinding lap.
•an ability to easily remove the mounted (dopped) stone for inspection and the ability to return it to its precise position when remounted in the machine.

There are two basic mechanical approaches to solving the problems of achieving the above requirements.

•The "Platform" or "Floating Head" machine
•The "Mast" machine
The majority of machines of modern design are of the mast type.


The Platform Type
The Raytech Shaw machine is a good example of this type. The stone is dopped and mounted in a handpiece which is not fixed or attached to the machine but which is placed on a platform which may be accurately raised or lowered by fine degrees. The handpiece may be lifted off to allow close inspection of the progress of cutting. This handpiece arrangement is somewhat similar to that used on diamond cutting machines and which can be seen in historical illustrations. Please note that the water pot and spigot arrangement is home made and not exactly what is issued with the machine.

The Raytech machine set up for use
Handpiece from book dated 1754
Modern Raytech handpiece
The Mast Type
The UltraTec illustrated here is of the mast type. The vertical thick steel rod or mast on which the faceting head moves up and down can be plainly seen, as can the screw mechanism which raises and lowers the head as required..
UltraTec machine set up for use
Closer view of faceting head.
The black dial is the angle indicator and the white dial is the depth indicator.