Handling and installation damage
Nicks, gouges and dents put there before the bearing ever ran. Urgency
Permanent dents from overload, impact, rough mounting or trapped debris.
What handling and installation damage looks like
- Nicks and dents on a ring, roller or cage, with raised edges around them
- Evenly spaced marks at roller or ball spacing, from a bearing forced on through the rolling elements
- A chipped or broken small rib, a deformed cage, or a dented cup face from a hardened driver
Rotec AI schematic illustration. It shows the typical pattern and is not a photograph of a real bearing.
How handling and installation damage develops
Every raised edge around a dent is a stress riser. When a rolling element goes over it the contact stress jumps, and a spall starts from that spot. A hammer, a hardened drift, a dropped bearing, or pushing the loose ring all leave damage that shows up as noise and vibration the day the machine starts, and as early spalling soon after.
How fast it progresses: The damage spreads from the dent. Noise and vibration are present from the first run, so do not wait for them to settle.
Causes of handling and installation damage
Mounting, handling & storage
- Hammering on a bearing, using a hardened driver or mild-steel bar of the wrong grade, applying force through the rolling elements (loose ring)
- Rollers hitting the raceway while the bearing is slid into place
Design & seats
- No room for a proper mounting tool, or no way to apply force to the tight ring
Environment & sealing
- Dirt carried in by tools, hands and work surfaces
How to confirm it is handling and installation damage
- Measure the spacing of the dents: if it matches the roller or ball pitch, the force went through the rolling elements
- Look for raised edges: handling damage has them, wear marks (false brinelling) do not
- Check the failure time: damage that starts within hours or days of a rebuild points to handling
How to fix and prevent handling and installation damage
- Press or heat the bearing on, and push only on the ring that has the tight fit
- Use proper fitting tools or induction heaters, never an open flame
- Keep bearings in their packing until the moment of fitting, and keep tools clean
- Scrape or grind down any burr or high spot in a housing seat before refitting an outer ring
Easily confused with
- Overload deformation (true brinelling): True brinelling is a dent from overload or shock in service: look at the load history.
- False brinelling: False brinelling wears the surface and leaves no raised edge.
Catching handling and installation damage early
Impact damage shows at the ring or element defect frequency from the very first day. A baseline reading taken right after a rebuild will catch a damaged bearing before it spalls.
Other dent modes
Questions about handling and installation damage
What causes handling and installation damage in a bearing?
Hammering on a bearing, using a hardened driver or mild-steel bar of the wrong grade, applying force through the rolling elements (loose ring). No room for a proper mounting tool, or no way to apply force to the tight ring. Dirt carried in by tools, hands and work surfaces.
How do you fix or prevent handling and installation damage?
Press or heat the bearing on, and push only on the ring that has the tight fit. Use proper fitting tools or induction heaters, never an open flame. Keep bearings in their packing until the moment of fitting, and keep tools clean.
What does handling and installation damage look like?
Nicks and dents on a ring, roller or cage, with raised edges around them. Evenly spaced marks at roller or ball spacing, from a bearing forced on through the rolling elements.