Through-hole ruby bearings are precision-engineered components made from synthetic single-crystal ruby (Al₂O₃ doped with Cr₂O₃). These bearings feature a central through-hole structure that allows shafts, pins, or optical fibers to pass through smoothly while minimizing friction and wear. Ruby's extreme hardness (Mohs 9), outstanding chemical stability, and excellent surface finish make these bearings ideal for precision instruments, metering devices, fiber optic assemblies, and micro-mechanical systems where stability and long lifespan are critical.

The bearing body consists of synthetic corundum crystal, grown under controlled conditions to ensure uniform hardness and purity. Chromium doping gives the material its characteristic red color while enhancing optical clarity and corrosion resistance. The through-hole is precisely machined and polished to achieve micron-level dimensional accuracy and smoothness, ensuring excellent coaxiality and low friction in rotary or oscillating movement.

• Material: Synthetic Ruby (Al₂O₃ + Cr₂O₃)
• Hardness: Mohs 9
• Density: 3.98 g/cm³
• Operating Temperature: -60°C to +500°C
• Hole Diameter: 0.05-5.0 mm (customizable)
• Outer Diameter: 0.5-10 mm (customizable)
• Concentricity Tolerance: ≤ 0.003 mm
• Surface Roughness: Ra ≤ 0.02 μm

• Ultra-High Hardness & Wear Resistance: Ruby's exceptional hardness ensures minimal abrasion, maintaining stable dimensions over years of operation.
• Smooth and Precise Rotation: The through-hole design and optical-level surface polish guarantee low friction and high rotational accuracy.
• Chemical & Thermal Stability: Ruby bearings withstand acids, alkalis, solvents, and high temperatures without deformation or corrosion.
• Excellent Dimensional Precision: Each bearing is precisely lapped and inspected to meet strict concentricity and parallelism standards.
• Long Service Life: Even in high-speed or continuous-contact applications, ruby bearings maintain performance without requiring lubrication.

• Precision Measuring Instruments: Used in dial indicators, micrometers, and flow meters for stable, friction-free movement.
• Fiber Optic and Laser Systems: Serves as alignment and support components in optical connectors and light transmission assemblies.
• Watchmaking and Micro Motors: Provides low-friction pivoting for high-precision miniature shafts.
• Medical and Analytical Equipment: Ensures accurate motion in miniature pumps and sensor mechanisms.
• Aerospace and Defense Devices: Ideal for compact, durable, and vibration-resistant bearing solutions.

• No oxidation or rusting
• No magnetic interference
• No need for lubrication
• Higher hardness and smoother operation
• Longer operational lifespan

Each through-hole ruby bearing undergoes 100% inspection for dimensions, hole alignment, and surface finish. We offer custom designs for diameter, thickness, and hole geometry to meet unique application requirements. Assemblies combining ruby bearings with stainless steel or ceramic housings are available upon request.