a possible fix for bearings that can run smoothly at low speed but lock up at high speeds. The most common cause of this condition is a loose and deformed bearing cage, and this method addressed this particular cause.
The condition itself often causes the bearing to become responsive on a strong and/or vibey throw, but may still remain unresponsive when the yoyo has slowed down. It is also easily diagonsed by flicking the bearing with your finger.
The procedure may also fix crown-caged bearings that produce an intermittent metal screech.
Warning: This procedure is by nature destructive. If you think you may still be able to fix the bearing through other means, save this as last resort only.
Contraindications: This procedure can almost certainly destroy ceramic or non-stainless bearings.
This method seem to work better (or technically, easier to do right) on crown (single) caged bearings than on chain (double) caged bearings.
My current record is 6/7 for crown bearings but only 2/4 for chain caged ones.
- Clean the bearing thoroughly by normal means. The bearing should be relatively quiet and smooth as long as the speed is low.
2. (optional/no strong evidence) Soak the bearing with water, freeze it for 10-20 minutes. After drying, rinse it with the organic solvent again. There has been a single case where a chain cage bearing was already working properly after this step, and a crown cage bearing became smoother.
- Insert several thin needles between the cage and the outer race to squeeze the cage toward the center. For crown cage bearings, the needles should go in from the opening side to put more pressure on the lobes.
- Burn it over a fire until a slighest tint of oxidation develops. 1 cm over a spirit lamp flame tip or <0.5cm over a candle flame (closest not to produce carbon ash) for 2 minutes both produced similar results. Other sources (gas/bunsen lamp etc) have not been tested. For crown bearings it may be benificial facing the open side down.
- Quench in water and dry at room temperature.