440 Stainless Steel Deep Groove Ball Bearings S684 S685 S686 S687 - S699

Match the bearing bore (ID) to your shaft diameter and the outer diameter (OD) to your housing bore. The width (thickness) must fit within your available axial space. Use the "ID × OD × Thickness" option selector to find the exact size. If your shaft is 6 mm, for example, you would choose S686 (6×13×5 mm) or S696 (6×15×5 mm) depending on the OD your housing accepts.

Both series share similar bore diameters (4–9 mm) but differ in outer diameter and width. The S69x series (S694–S699) generally has a larger OD for the same bore, providing higher load capacity and a wider contact footprint. Choose S68x for space-constrained designs and S69x where higher radial stiffness is needed.

These are open (unshielded) bearings. They allow for re-lubrication and are suitable for clean or lightly contaminated environments. If your application involves significant dust, debris, or liquid ingress, consider adding external seals or selecting a shielded variant. Contact us if you need shielded or sealed versions of these sizes.

AISI 440 stainless steel offers substantially better corrosion resistance than standard GCr15 (52100) carbon steel bearings. It resists rust in humid air, fresh water splash, and mild acidic or alkaline environments. However, it is not fully immune to chloride-rich environments (e.g., saltwater immersion) — for those conditions, 316 stainless or ceramic bearings are more appropriate.

Yes. The deep groove geometry allows these bearings to carry moderate axial loads in both directions alongside their primary radial load. They are not designed for pure thrust applications — for high axial loads, angular contact or thrust bearings are more suitable. For combined radial and moderate axial loads (common in motors, gearboxes, and actuators), these bearings perform well.

For most applications, a light lithium-based grease (NLGI Grade 2) applied sparingly to the raceway is sufficient. For high-speed or low-torque applications, a light spindle oil may be preferable. Re-lubrication interval depends on operating speed, load, and environment — typically every 500–2,000 operating hours for moderate-duty use. Contact us to confirm lubrication recommendations for your specific conditions.

Yes. The S684–S699 size range is widely used in RC vehicles, brushless motor assemblies, drone arm pivots, and robotic joint mechanisms. The stainless steel construction handles the vibration, occasional moisture exposure, and repeated load cycles typical of these applications. The small bore sizes (4–9 mm) align with common motor shaft diameters in this segment.