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Nut Strength Class — ISO 898-2
Look up ISO 898-2 nut classes: proof load stress, hardness range, and matching bolt property class. Select nut class and size.
Results
Proof Load
The proof load of a nut is the maximum axial force it can withstand without permanent deformation:
ISO 898-2 Nut Class Summary
| Nut Class | Sp (MPa) ≤M16 | HV Range | Matching Bolt |
|---|---|---|---|
| 5 | 500 | 130–302 | 4.6, 4.8, 5.6, 5.8 |
| 6 | 600 | 150–302 | 6.8 |
| 8 | 800 | 200–302 | 8.8 |
| 10 | 1040 | 260–353 | 10.9 |
| 12 | 1220 | 295–353 | 12.9 |
⚠️ Note: For sizes >M16, ISO 898-2 tabulates size- and style-dependent proof load stresses that can differ from the class nominal value shown here (for some classes they are higher, not lower). Always verify the proof load against the actual ISO 898-2 table for the exact size, pitch and nut style.
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Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
