Property Class 12.9 Steel EPDM Rubber Well Nuts are supplied to ISO 898-1 property class 12.9. Corrosion behaviour is requires plating or black-oxide protection, the material is magnetic, and the usable service range is commonly limited to approx. +300 °C; confirm against the coating and the load. In practice this grade is the highest common strength class, for high-load machine assembly.
- Grade
- ISO 898-1 property class 12.9
- Corrosion resistance
- Requires plating or black-oxide protection
- Magnetic response
- Magnetic
- Service temperature
- commonly limited to approx. +300 °C; confirm against the coating and the load
Property values are typical for the grade. Certified mechanical test data is available on request for production orders.
Property Class 12.9 Steel EPDM Rubber Well Nuts are supplied to our own published dimensions — this is a trade-series article rather than one covered by a dimensional standard, so confirm the figures against the part you are replacing. The grade provides requires plating or black-oxide protection and is magnetic; the practical service range is commonly limited to approx. +300 °C; confirm against the coating and the load.
Why Choose Property Class 12.9 Steel for EPDM Rubber Well Nuts
The highest common strength class, for high-load machine assembly. For epdm rubber well nuts, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|
| Magnetic response | Magnetic |
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| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating or black-oxide protection |
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Galvanic & Galling Considerations
For epdm rubber well nuts in steel, the dominant compatibility issue is hydrogen embrittlement at high property classes (10.9 and above) when electroplated. Plating must be followed by an appropriate baking treatment, or a non-electroplated finish (mechanical zinc, zinc flake) should be substituted.
Comparable Grades
For EPDM Rubber Well Nuts, class 8.8 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of EPDM Rubber Well Nuts Available in Property Class 12.9 Steel
| Thread size | Representative hole diameter (mm) | Representative grip range (mm) | Temperature range (u00b0C) | Representative tightening torque (Nu00b7m) | Body / insert |
|---|
| M3 | 8.0 | 0.4~4.0 | -30~+80 | 0.5 | EPDM rubber / stainless threaded insert |
| M4 | 8.0 | 0.4~4.0 | -30~+80 | 0.4 | EPDM rubber / stainless threaded insert |
| M5 | 9.7 | 0.4~4.9 | -30~+80 | 0.6 | EPDM rubber / stainless threaded insert |
| M6 | 12.8 | 0.4~4.0 or 0.8~4.7 | -30~+80 | 1.0 | EPDM rubber / stainless threaded insert |
| M8 | 16.0 | 0.4~4.0 | -30~+80 | 1.5 | EPDM rubber / stainless threaded insert |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this nut in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Locking method is specifiable independently of the rest: nylon insert, all-metal deformed thread, serrated flange, or none. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom nut manufacturingSend a drawing
Applications & Industries
Where EPDM Rubber Well Nuts are used, and what decides the specification in each case. Stocked from M3 to M8.
Industries that specify EPDM Rubber Well Nuts
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Vehicle body panels
Rubber well nuts isolate and seal trim fasteners through thin skins.
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Motorcycle service
Blind rubber inserts provide a thread where the rear face is inaccessible.
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Outdoor enclosures
EPDM accommodates panel movement and keeps a small hole sealed.
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Equipment covers
Stainless inserts resist corrosion while the rubber body clamps the panel.
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Maintenance & MRO
Replacements matched to the existing bolt class, thread and finish.
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Building services
Threaded rod, channel and suspension assemblies.
Typical applications
- adding a blind threaded point to a thin panel
- matching hole diameter and grip range to the EPDM body
- tightening only to the representative torque for the size
- using the rubber body for isolation and sealing
- completing a bolted joint on a stud, rod or bolt
- locking an adjustment so it cannot drift
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- Sealed joints
- Used where the fixing has to keep water or air out as well as hold — the elastomer, not the fastener, decides service life.
- Match the class
- A nut below the bolt property class strips before the bolt reaches its own limit — pair class 8 nuts with 8.8 bolts, class 10 with 10.9.
Where to use something else
- Do not over-tighten a well nut; excess compression can pull the insert through the panel or damage the seal.
Full application guide: where EPDM Rubber Well Nuts are used, how to specify them, and the cases they are wrong for
