The Diamond Cutting Wheel (16.09)
The fast rotating (2500-5000 rpm), steel or cast-iron traditional diamond cutting wheel, commonly referred to as a scaif, is pre-scoured, with a grooved finish over the entire surface to hold the manually applied olive oil and diamond dust mixture, (a slurry or paste-like consistency), in place while the diamond is being polished by applying force. The cutter generally has three cutting rings on the wheel, consisting of the innermost, the starting ring, the second or middle, the cutting ring, and the last or outer, the smoothing ring. The starting ring is a test area to make sure the cutter knows he is in perpendicular direction to the single grain (commonly called “on grain”). This spares the primary cutting ring from unnecessary wear during the process of locating the best cutting position.
In 1475 Lodewyk van Bercken of Bruges Flanders" who is often referred to as "The Father of Modern Diamond Cutting" invented the scaif giving cutters the ability to grind and polish flat facet shapes onto rough diamond, transforming the often opaque crystals into reflective beauties discovering their further potential of optical properties.
Above image courtesy of: https://en.wikipedia.org/wiki/Diamond_cutting
Before the scaif invention, diamonds were highly prized but limited the cutters to rubbing two diamonds together or using abrasives like diamond sandpaper, (diamond fragments embedded into animal hide or a plant-based foundation like horsetail). This limited the finished products to something of resembling the original crystal's form such as a point cut, with largely unpolished octahedral faces left in place.
Above image by Glenn Lovelady
The above image is courtesy of: https://www.indiamart.com/