Low-Temperature Resistance 7009c Single-Row Customisable Angular Contact Ball Bearing for Machine Tools

Skidding occurs when the axial preload is insufficient, causing the balls to slide rather than roll at high speeds. You must ensure the bearing is mounted with the correct preload class (Light, Medium, or Heavy) corresponding to your specific RPM and cutting load to maintain traction between the balls and raceways.

You likely installed them in a Tandem (DT) arrangement instead of Back-to-Back (DB) or Face-to-Face (DF). Tandem only supports thrust in one direction. For reversing axial loads, a DB or DF duplex configuration is mandatory to lock the shaft in both directions and eliminate axial play.

Striking the bearing transfers impact force through the rolling elements, permanently denting the raceway. You must use a bearing heater or proper installation fixture. Never apply pressing force across the balls; only press the ring that is being mounted with an interference fit.

You likely mixed different grease brands. Mixing incompatible thickeners causes severe chemical reactions that lead to rapid grease degradation and total lubrication failure. Always replenish with the exact same brand every 6 to 12 months, or thoroughly flush the housing first.

Uneven tightening distorts the raceway geometry, destroying the bearing's precision. Technicians must use a torque wrench to tighten the end screws in a strictly controlled 3-stage sequence: 40%, 70%, and finally 100% of the rated torque, following a 'cross pattern' for perfect load distribution.