Grease Compatibility Evidence Worksheet
Classify the evidence for one exact pair of lubricating greases. This worksheet does not predict compatibility from thickener names, base-oil families, NLGI grade or a generic matrix. It does not authorize mixing or prescribe a universal changeover procedure.
Document the exact pair and evidence
Use full manufacturer and product designations, including formulation/revision where available. A family name such as “lithium”, “polyurea” or “NLGI 2” is not a product identity.
Evidence basis
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Next action
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What this does not prove
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ASTM D6185-24 decision logic
The current ASTM store record identifies ASTM D6185-24 as Active, last updated 5 December 2024. It is a laboratory practice for evaluating one or three binary mixtures of two exact lubricating greases relative to the neat greases. It is not a universal thickener compatibility table.
| Evidence | Worksheet classification | Limite |
|---|---|---|
| Any tested mixture fails any primary test | Incompatible by reported test result | ASTM states testing stops at the first failure. |
| All tested mixtures pass all three primary properties | Compatible in D6185-24 primary-test scope | Secondary testing may still be appropriate; application suitability is separate. |
| Composition chart, one property, incomplete summary or no exact-pair report | Unverified | Do not convert “unknown” or “individual testing required” into “borderline”. |
| Confirmed identical product | Not a binary mixture of different greases | Still verify formulation/revision, condition, contamination control and OEM servicing instructions. |
Primary protocol disclosed by ASTM’s public scope
| Article | Publicly disclosed D6185-24 scope |
|---|---|
| Mixtures | 50:50; when three ratios are evaluated, 10:90 and 90:10 represent attempted changeover/purging conditions. |
| Dropping point | ASTM D566 or ASTM D2265. |
| Shear stability | ASTM D217, 100,000-stroke worked penetration. |
| Elevated-temperature storage stability | Change in 60-stroke penetration using ASTM D217. |
| Decision | Any primary-test failure → incompatible; all tested mixtures pass all three → compatible in this practice’s scope. |
Acceptance calculations, preparation details and mandatory procedural requirements must be taken from the licensed standard. This page does not invent clause numbers or limits.
Why the former matrix was removed
ASTM D6185-24 states that compatibility cannot be predicted with certainty from grease composition; even nominally similar thickeners can be incompatible because of additive treatments. The previous page nevertheless returned “fully compatible” for equal thickener labels, returned “borderline” for unspecified pairs and issued categorical claims for polyurea and base-oil families.
SKF’s Super-precision bearings catalogue (PUB BU/P1 13383/2 EN, March 2016), tables 30–31, contains composition-based guidance for that bearing scope, but SKF explicitly says those tables are guidelines and recommends expert verification and application testing. Its entries also materially disagree with the former site matrix for multiple pairs. A scoped manufacturer chart therefore cannot be silently converted into a universal calculator.
Fixed purge multiples, universal cycle counts and fixed monitoring windows were also removed. Purge volume, solvent use, disassembly, venting, over-greasing risk and monitoring limits depend on equipment design and the controlled OEM procedure.
Primary and manufacturer sources
- ASTM D6185-24 official record — Active; exact-pair binary-mixture test protocol and public decision scope.
- SKF Super-precision bearings, March 2016, tables 30–31 — composition tables are explicitly guidelines; SKF calls for expert verification and application testing.
- ExxonMobil Aviation grease compatibility and conversion — exact formulations, testing and OEM cleaning instructions; aviation practice is more restrictive.
- Shell AeroShell grease FAQ — additive interactions matter and products approved to the same specification can still be incompatible.
Accessed 12 July 2026. Always use the current controlled OEM/service document for the actual machine.
