Practical FAQs
Q1: Can I use a thrust ball bearing to support a vertical shaft?
Absolutely. This is one of their most common applications (e.g., vertical pumps, turntables). However, you must ensure that even when idle, the shaft washer is under at least a minimal preload or gravity force. If the load drops below a minimum threshold, the balls may skid, causing wear.
Q2: Why can't I just replace a broken one with a deep groove ball bearing?
Because they are structurally incompatible. Thrust ball bearings have no radial load capacity. If you attempt to install them where a radial load exists, the balls will ride up the shoulders of the raceway, causing extremely high edge stress and rapid fracture of the cage. For combined loads, you must use an angular contact bearing or a combination of radial and thrust bearings.
Q3: I've always heard they are terrible for high speeds. Why?
Due to centrifugal force. The balls are pushed outward by centrifugal force, which severely distorts the contact angles and increases friction. Unlike radial bearings where centrifugal force is distributed across the raceway, in thrust bearings, it causes massive sliding friction. For high-speed axial loads, we recommend Angular Contact Thrust Ball Bearings or Thrust Cylindrical Roller Bearings.
Q4: What lubrication do they need?
Because the balls are sliding (not rolling) during high-speed operation due to centrifugal force, they require high-viscosity oil for proper hydrodynamic lubrication. Grease is generally limited to very low-speed applications (under 500 RPM). For high-speed vertical shafts, an oil bath or forced oil circulation is mandatory.
