NLGI Consistency Grade

NLGI (National Lubricating Grease Institute) grades run from 000 (semi-fluid) to 6 (very hard). In Singapore’s industrial applications:

NLGI Grade	Consistency	Typical Application
NLGI 00 / 0	Semi-fluid to very soft	Enclosed gearboxes, centralised lubrication systems
NLGI 1	Soft	Slow-speed or cold-climate bearings — rarely used in Singapore
NLGI 2	Medium	Most Singapore applications — bearings, chassis, hubs
NLGI 3	Firm	High-temperature or vertical applications prone to grease slump
NLGI 4–6	Hard to very hard	Block grease for open gears, wire ropes, specialised contacts

For Singapore: NLGI 2 is the default for most bearing and chassis applications. Step up to NLGI 3 for high-temperature oven, kiln, or exhaust-adjacent applications.

Thickener Types

Lithium (Li) and Lithium Complex (Li-X)

The most widely used thickener globally and in Singapore. Lithium grease handles 120°C (plain lithium) or 180°C+ (lithium complex). Good water resistance, compatible with most seal materials, available in EP (extreme pressure) formulations for heavily loaded bearings.

Calcium Sulphonate (CaSO)

Excellent water resistance and inherent EP performance — well suited for Singapore marine, port, and outdoor applications where wash-out resistance is critical. Higher cost than lithium but significantly better in wet environments.

Polyurea

Preferred for electric motor bearings — long life, high temperature capability (200°C+), clean-burning. Not compatible with lithium grease — purge thoroughly before switching.

Bentonite (Clay)

No drop point (does not melt) — used in extreme-temperature applications (oven chains, kiln bearings above 200°C). Poor water resistance — not suitable for outdoor use in Singapore humidity.

EP (Extreme Pressure) Grease

EP additives (sulphur-phosphorus or solid lubricants like MoS₂ or graphite) protect against metal-to-metal contact under heavy shock loads. Use EP grease for:

• Heavily loaded slow-speed bearings (crane slewing rings, conveyor idlers)
• Universal joints, king pins, fifth wheels on commercial vehicles
• Open gear drives and rack-and-pinion systems
• Excavator bucket pins and boom bushings

Do not use EP grease in high-speed bearings — the EP additives are abrasive at low loads and generate heat above threshold speeds.

Grease Compatibility — A Common Mistake

Mixing incompatible greases can cause complete structural breakdown, leaving bearings with no lubrication. Always purge the old grease completely before switching thickener type. Key incompatible pairs in Singapore workshops:

• Lithium vs polyurea — incompatible; causes softening
• Lithium vs calcium complex — borderline; test before committing
• Sodium soap (old type) vs lithium — incompatible and sodium soap has poor water resistance anyway

If unsure, default to lithium complex NLGI 2 EP — compatible with most lithium greases and widely stocked in Singapore.

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