Faceting machine

A faceting machine is broadly defined as any device that allows the user to place and polish facets onto a mineral specimen. Machines can range in sophistication from primitive jamb-peg machines to highly refined, and highly expensive, commercially available machines. A major division among machines is found between those that facet diamonds and those that do not. Specialized equipment is required for diamond faceting, and faceting as an occupation rarely bridges the gap between diamond and non-diamond workmanship. A second division can be made between industrial faceting and custom/hobby faceting. The vast majority of jewelry-store gemstones are faceted either abroad in factories or entirely by machines. (Diamonds are the exception, owing to the training and specialized equipment required to facet them.) Custom jewelry is still commonly made of custom metalwork and mass-produced gemstones, but unusual cuts or particularly valuable gemstone material will likely be faceted on a personal faceting machine.

A number of manufacturers sell non-commercial faceting machines. Among the more common names are Ultra-Tec, Facetron, Graves and Poly-Metric, although there are many competing brands. They range in price from just over $1,000 to upwards of $4,000.

The essentials of how a faceting machine works will be explored through this type of machine. There are two major components of a faceting machine: The mast/head assembly, and the grinding wheel, or lap. A rough piece of mineral is attached to the head, and through angle, rotation, and height adjustments of the head, the mineral is lowered into contact with the grinding wheel until a facet has been ground.

The mast assembly is the heart of the faceting machine. The rest of the machine is simple in construction, including the arbor for the grinding wheel, the motor that runs the arbor, a drip tank, and the controlling switches. These are described below:

Arbor: Similar to the prong in the middle of a record player, onto which the record is placed. The lap, or grinding wheel, is placed onto it rather than a record, and the arbor is machined to run perfectly flat when turning.

Arbor Nut: The screw that fits through the top of the lap and secures it to the arbor.

Motor: Typically the motor is housed beneath the machine and is attached by one of several means to the arbor. Motors are always velocity-variable and some can be reversed, i.e. clockwise as well as counterclockwise.

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