Bruting

Bruting is a part of the process for shaping diamonds used in watch-making and jewellery. It involves setting the diamonds on central rotating axles so that they can grind against each other in order to create a rounded shape.

The benefit of using jewel lined pivot holes for carrying spindles include predictable friction, improved wearing life and an ability to operate without lubrication, modern watches tend to use synthetic ruby or sapphire lined bearings.