Jewel bearing


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Jewel bearing

A bearing used in quality timekeeping devices, gyros, and instruments, usually made of synthetic corundum (crystallized Al2O3) which is more commonly known as ruby or sapphire. The extensive use of such bearings in the design of precision devices is mainly due to the outstanding qualities of the material. Sapphire's extreme hardness imparts to the bearing excellent wear resistance, as well as the ability to withstand heavy loads without deformation of shape or structure. The crystalline nature of sapphire lends itself to very fine polishing and this, combined with the excellent oil- and lubricant-retention ability of the surface, adds to the natural low-friction characteristics of the material. Ruby has the same properties as sapphire. See Antifriction bearing

References in periodicals archive ?
Every jewel bearing the Ploi Thai brand would be symbolic of being manufactured in Thailand and a proud addition to a jewellery lover's collection," he added.
The ABS impeller spins on a high precision jewel bearing.
The bob sits on a low friction jewel bearing and is driven by the rheometer through magnetic couplings.
Nielsen-Kellerman approached Bird Precision, Waltham, MA to help in the design of an ultra sensitive, low friction jewel bearing and alloy impeller shaft.
Sapphire jewel bearings suspend the turbine, allowing for sensitivity to the slightest movement.
B brushless DC motor is now composed of jewel bearings.
Responding to the lightest winds, the turbine is suspended on sapphire jewel bearings.
Around the mid-forties, in the course of an investigation on jewel bearings for instruments, conducted under authorization of the Bureau of Aeronautics, United States Navy, NBS made a number of tests and examinations of various materials, included corundum (natural and synthetic), synthetic spinel and glass (12).