The standard for oiling cap jewels includes perfectly clean jewels with oil expanding to fill an area with a diameter equal to between 1/2 and 2/3 of the diameter of the cap jewel. The oil circle should be perfectly round and concentric to the circumference of the jewel. If it is not, either the cap jewel is not seated parallel to the hole jewel, or there is some contamination drawing the oil away. The jewel should be disassembled, checked, cleaned, reassembled, and oiled to resolve the problem. Too little oil will result in the oil evaporating before the service interval is up. Too much oil will result in the oil contacting the edge of the jewel during a shock and “wicking” away, leaving a dry jewel that will become damaged and result in poor timekeeping of the watch.
