Girdling (Bruting) (16.13)
Girdling, often called bruting, is the shaping of the elliptical cuts. This would include the round brilliant, pear shape, oval, marquise, and heart shape. Frequently a bruter is a specialist in just that. A polisher will rough-in a stone to get the basic layout, then hand it over to the bruter who gives it a preliminary, or a final girdle. Today bruting is done using a lathe-like machine where as the diamond is glued or clamped on to the girdling machine. Another industrial-grade diamond is used by mounting it in a girdling stick or another clamp in modern machines. The image below is for illustrative purposes. The sawed half would first need to be roughed in on the polishing wheel before adding the preliminary girdle.
The above image is courtesy of: https://www.tradeindia.com/
Types of Diamond Bruting Machines
The high-resolution dual cameras for top and side views, with contact probes that scan the diamond so manual centering errors are eliminated. Some systems use cooling liquid to prevent thermal stress, bearding and safety around inclusions that could potentially fall out. The software that is used is a sophisticated proprietary application for precise shaping in achieving maximum weight retention that can include CNC with multi-axis synchronization and artificial intelligence bringing the accuracy to a sub-micron level.
