681
L-310
LF-310
-
1
3
1
0.03
3.8
0.3
0.3
The 681 OPEN is a 68-series miniature deep groove ball bearing with a 1 mm bore (d), 3 mm outside diameter (D) and 1 mm width (B). It has an open construction — no metal shields or rubber seals on either side. With this design, lubricant retention and contamination protection depend largely on the surrounding equipment and its lubrication setup. If your mechanism already provides external lubrication, or runs in a relatively clean, enclosed environment, the open type can be considered. Suitability still needs to be confirmed against the actual application.
Because the open type has no built-in shielding, both lubricant supply and the exclusion of contaminants sit on the equipment side. It helps to confirm: whether the operating environment contains dust, moisture or chips; and how lubrication is provided — external supply, oil bath, or reliance on factory lubrication. At this size, lubrication condition and cleanliness directly affect running behaviour, which is what the open version needs clarified more than the other two.
With a 1 mm bore, fit tolerances and the machining accuracy of the shaft and housing are sensitive, so selection should not rest on the model number alone. If you can share the speed and operating environment, we can help assess whether the open type is suitable, or whether a shielded version fits better. If you already have a model number, drawing or sample, feel free to include it, and we will help with the next step.
Some non-standard or currently out-of-stock bearings may not be immediately available. If you have specific requirements, feel free to contact us — we will do our best to confirm lead times and provide alternative solutions.
