How to lubricate a deep groove ball bearing?

Deep Groove Ball Bearing Lubrication Practical Guide

1. Grease or Oil?

Grease (butter) is preferred in 90% of cases:

Sealed/Dustproof Bearings: Comes with grease from the factory and doesn't need refilling during its lifespan (e.g., washing machine bearings).
Open Bearings: Use lithium-based grease NLGI 2 universal type, inexpensive and heat-resistant.

Oil is only suitable for special scenarios:

Ultra-high speed electric spindles (>15,000 rpm) – use thin oil circulation cooling; avoid this for ordinary equipment.

2. Lubrication Tips (Hand Application Version)

Grease Amount: Fill the bearing's internal space to 1/3 (better too little than too much):
Overfilling → stirring and heating → oil leakage → dust accumulation.
Method: Use your fingers to apply grease into the gaps between the balls, spreading it evenly in a circular motion.
Before installing the sealing ring, apply a thin layer of grease to the lip to prevent dry friction.

3. How Often Should You Refill?

4. Damaging Bearings with Inferior Lubricants

Mixing Greases:

Lithium-based grease + calcium-based grease = caking → clogging the raceway.

Using WD-40 as Lubricant:

Dries after two days of use → metal grime forms.

Using a High-Pressure Water Gun to Clean Bearings:

Water is forced into the seals → grease emulsifies → rust through the raceway.

5. Grease Replacement and Refurbishment Steps

Removing Old Grease:

Soak the bearing in diesel or kerosene, and clean the raceway residue with a toothbrush.

Drying:

Blow away grease stains from gaps with compressed air (or absorb with paper towels). Applying new grease: Apply grease to your finger and insert it between the ball bearings, rotating it a few times to allow it to penetrate.

6. Special Warning for Sealed Bearings

Do not pry open the seal:

Deformation of the rubber lip → Water and dust ingress → Premature failure.

Signs of failure:

Cracked or hardened seal → Replace the bearing immediately; adding grease will not save it.