TECHNICAL REFERENCE · GLOSSARY
The terms and reference tables behind every TDS.
A technical data sheet assumes you already know what "demulsibility," "AGMA lubricant number" or "load wear index" mean. This page defines the terms MOTTA's own TDS and OHI documents use, and carries the standard reference tables (ISO viscosity grade, NLGI grease consistency, AGMA gear oil) so you can check a figure without leaving this page.
Additive terminology
Additives are compounds blended into a base oil to give it a property the base oil doesn't have on its own, or to strengthen one it already has.
| Term | Definition |
|---|---|
| Anti-wear (AW) additive | Reacts with rubbing metal surfaces to form a protective film, reducing wear from surface-to-surface contact under normal operating loads. |
| Extreme pressure (EP) additive | Activated by the high contact pressure and frictional heat found in heavily loaded gears (worm gears in particular) — forms a sacrificial film that prevents welding and scoring under shock loads that an AW additive alone can't handle. |
| Antioxidant | Slows the reaction between the oil and oxygen that otherwise breaks the oil down into acids, sludge and varnish over time. |
| Rust inhibitor | Improves the oil's ability to resist rusting of metal surfaces — the baseline pass/fail test is ASTM D665. |
| Rust & oxidation (R&O) inhibitor | Shorthand for an oil formulated with both rust-inhibiting and oxidation-inhibiting additive packages — common terminology for turbine, circulating and general industrial oils. |
| Anti-foam additive (foam suppressant) | Weakens the surface film between air bubbles in the oil so they collapse instead of persisting as foam. |
| Pour point depressant | Suppresses the growth and clustering of wax crystals at low temperature, lowering the temperature at which the oil stops flowing. |
| Thickener | Solid particulates (metallic soap, or a non-soap thickener) dispersed through a liquid lubricant to form grease — the thickener holds the base oil in a semi-solid structure until mechanical or thermal action releases it. |
| Filler | A solid additive such as mica, graphite or various powdered minerals, added to increase consistency or load-carrying ability, mainly in grease. |
| Tackiness agent (adhesive property) | Improves the oil film's ability to cling to a metal surface — relevant on open gears, wire ropes and other applications where the oil would otherwise be thrown off by centrifugal force or gravity. |
Performance and physical property terminology
These are the properties a TDS actually measures, and what each one is telling you about the oil.
| Term | Definition |
|---|---|
| Soap base | The general term for a metallic thickening salt used in grease manufacture — lithium, sodium, calcium, barium and aluminium soaps are the common thickening agents. |
| Oil film strength | The lubricating film's resistance to rupture under combined load, speed and temperature. |
| Load-carrying capacity | A composite measure of an oil's ability to resist film breakdown and protect surfaces from wear and damage under high speed, high load and high temperature acting together. |
| Load Wear Index (LWI) | A wear-protection rating derived from the four-ball test — the load at which the oil's anti-wear film begins to fail under increasing pressure. |
| Timken OK Load | The maximum load an oil can sustain in the Timken EP test without the lubricating film rupturing. |
| Shear stability | An oil's resistance to a permanent drop in viscosity when subjected to mechanical shearing — relevant to multigrade and polymer-thickened oils in particular. |
| Oxidation stability | An oil's resistance to degradation from exposure to oxygen, heat or UV — the property antioxidant additives are formulated to protect. |
| Thermal stability | An oil's resistance to breakdown under sustained high-temperature service, independent of oxidation. |
| Demulsibility (anti-emulsion property) | An oil's ability to separate cleanly from water rather than forming a stable emulsion — critical for hydraulic and turbine oils where water ingress is a realistic operating condition. |
| Detergency (cleanliness) | The oil's ability to prevent sludge and deposit formation at elevated temperature or under acidic contamination, and to keep any deposits that do form suspended rather than baked onto hot surfaces. |
| Dispersancy | The oil's ability to keep insoluble contaminants suspended in fine, harmless particles rather than allowing them to agglomerate and settle out as sludge or varnish. |
| Dielectric strength | A measure of an insulating fluid's resistance to electrical breakdown — the figure is method-dependent, so always read it against the specific test method quoted. |
| Pour point | The lowest temperature at which the oil is observed to still flow under defined test conditions. |
| Flocculation point | The temperature at which wax crystals first appear as the oil is chilled under defined conditions — relevant to refrigeration oils. |
| Cloud point | The temperature at which the oil first turns visibly hazy on cooling, caused by wax or other solids beginning to crystallise out of solution. |
| Carbon residue (Conradson) | The residue left behind after a mineral oil sample is evaporated and burned under defined conditions — an indicator of the oil's tendency to form carbon deposits. |
| Cleveland Open Cup (COC) | The standard open-cup apparatus used to measure the flash point of most oils with a flash point above 79°C. |
| Interfacial tension | The energy present at the boundary between two immiscible liquids — used as one signal of an oil's tendency toward oxidation and contamination. |
| Aniline point | The lowest temperature at which equal volumes of aniline and the oil sample are fully miscible — a lower aniline point generally indicates a higher aromatic content. |
| Aromatics / naphthenes / paraffins | The three hydrocarbon families that make up a mineral base oil — paraffinic (open-chain, saturated), naphthenic (ring-structured, saturated) and aromatic (ring-structured, unsaturated) — the balance between them shapes the base oil's viscosity index, oxidation stability and low-temperature behaviour. |
| Solvent refining | A base-oil refining process that uses a solvent to selectively extract undesirable components and improve base oil quality. |
| Dewaxing | The process of removing wax from a lubricant distillate, either by solvent (physical separation) or by catalytic conversion. |
Definitions are written for practical technical review, adapted from MOTTA's internal technical training material and standard industry usage. For a formal specification, always refer to the cited test method (ASTM, ISO, DIN) rather than this summary.
ISO viscosity grade reference (ISO 3448)
Industrial oils are classified by ISO viscosity grade (ISO VG) according to kinematic viscosity at 40°C. The grade number is the midpoint of the viscosity range in cSt, and every real product must test within the stated min/max band to carry that grade.
| ISO VG | Midpoint, 40°C cSt | Min, cSt | Max, cSt |
|---|---|---|---|
| 2 | 2.2 | 1.98 | 2.42 |
| 3 | 3.2 | 2.88 | 3.52 |
| 5 | 4.6 | 4.14 | 50.6 |
| 7 | 6.8 | 6.12 | 7.48 |
| 10 | 10 | 9 | 11 |
| 15 | 15 | 13.5 | 16.5 |
| 22 | 22 | 19.8 | 24.2 |
| 32 | 32 | 28.8 | 35.2 |
| 46 | 46 | 41.4 | 50.6 |
| 68 | 68 | 61.2 | 74.8 |
| 100 | 100 | 90 | 110 |
| 150 | 150 | 135 | 165 |
| 220 | 220 | 198 | 242 |
| 320 | 320 | 288 | 352 |
| 460 | 460 | 414 | 506 |
| 680 | 680 | 612 | 748 |
| 1000 | 1000 | 900 | 1100 |
| 1500 | 1500 | 1350 | 1650 |
NLGI grease consistency reference (ASTM D217)
Grease consistency (NLGI grade) is measured by worked penetration — how far a standard cone sinks into the grease after 60 strokes, at 25°C. A lower NLGI number is a softer grease; a higher number is stiffer.
| NLGI grade | Worked penetration, 25°C (0.1 mm units) |
|---|---|
| 000 | 445–475 |
| 00 | 400–430 |
| 0 | 355–385 |
| 1 | 310–340 |
| 2 | 265–295 |
| 3 | 220–250 |
| 4 | 175–205 |
| 5 | 130–160 |
| 6 | 85–115 |
AGMA reference for enclosed gear drives
AGMA lubricant numbers classify industrial gear oils by viscosity range at 40°C (per ASTM System D 2422), alongside the equivalent ISO VG grade and the AGMA number for the synthetic gear oil equivalent.
| AGMA lubricant no. R&O gear oil | AGMA lubricant no. EP gear oil | Viscosity range, 40°C cSt (min) | Viscosity range, 40°C cSt (max) | Equivalent ISO VG | AGMA no. synthetic gear oil |
|---|---|---|---|---|---|
| 0 | — | 28.5 | 35.2 | 32 | 0S |
| 1 | — | 41.4 | 50.6 | 46 | 1S |
| 2 | 2 EP | 61.2 | 74.8 | 68 | 2S |
| 3 | 3 EP | 90 | 110 | 100 | 3S |
| 4 | 4 EP | 135 | 165 | 150 | 4S |
| 5 | 5 EP | 198 | 242 | 220 | 5S |
| 6 | 6 EP | 288 | 352 | 320 | 6S |
| 7, 7 Comp | 7 EP | 414 | 506 | 460 | 7S |
| 8, 8 Comp | 8 EP | 612 | 748 | 680 | 8S |
| 8A Comp | 8A EP | 900 | 1100 | 1000 | — |
| 9 | 9 EP | 1350 | 1650 | 1500 | 9S |
| 10 | 10 EP | 2880 | 3520 | — | 10S |
| 11 | 11 EP | 4140 | 5060 | — | 11S |
| 12 | 12 EP | 6120 | 7480 | — | 12S |
| 13 | 13 EP | 28800 | 35200 | — | 13S |
14R and 15R grades are specified at 100°C rather than 40°C (14R: 428–857 cSt; 15R: 857–35,200 cSt) and are omitted from the 40°C comparison above.