ring oiler - simple device for lubricating a journal bearing. A metal ring rides loosely on the journal shaft and the lower part of the ring dips into a small oil reservoir. The reservoir is fed by a bottle-fed oiler. The rotation of the shaft turns the ring, which carries oil up to the point of contact with the shaft and into the bearing. Though not ordinarily considered a circulating lubrication system, the ring oiler is similar in principle and generally requires a long-life oil of the R&O type.