Nuts · Trade series (self-clinching, IFI-111 practice)
Property Class 12.9 Steel Self-Clinching Press-Fit Nuts
Mechanical properties, corrosion behaviour and the full dimensional range for this grade.
Property Class 12.9 Steel Self-Clinching Press-Fit 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.
Hidden Deck Fasteners Sourcing: Manufacturing, Types & Material Compatibility
Property Class 12.9 Steel (ISO 898-1 property class 12.9) is the highest common strength class, for high-load machine assembly. When self-clinching press-fit nuts are specified in this grade, the dimensions remain per Trade series (self-clinching, IFI-111 practice); the material determines corrosion behavior (requires plating or black-oxide protection) and the service temperature range (commonly limited to approx. +300 °C; confirm against the coating and the load). Both are covered below with the size table.
Why Choose Property Class 12.9 Steel for Self-Clinching Press-Fit Nuts
The highest common strength class, for high-load machine assembly. For self-clinching press-fit 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
Service temperature
commonly limited to approx. +300 °C; confirm against the coating and the load
Corrosion characteristic
Requires plating or black-oxide protection
Galvanic & Galling Considerations
For self-clinching press-fit 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 Self-Clinching Press-Fit 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 Self-Clinching Press-Fit Nuts Available in Property Class 12.9 Steel
Thread size
Shank diameter (mm)
Length (mm)
Hole in sheet (mm)
Minimum sheet thickness (mm)
Maximum sheet hardness
Material
Installation
M3
4.20
3.30
4.22
0.8
HRB 80
Case-hardened steel
Press, squeeze
M4
5.40
3.80
5.42
0.8
HRB 80
Case-hardened steel
Press, squeeze
M5
6.35
4.20
6.38
1.0
HRB 80
Case-hardened steel
Press, squeeze
M6
7.95
4.80
7.98
1.0
HRB 80
Case-hardened steel
Press, squeeze
M8
9.55
5.70
9.58
1.5
HRB 80
Case-hardened steel
Press, squeeze
Technical Drawing
Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.
Sends the selected values to the quote form below.
Request a Quote
The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.
Dimensions & Specifications (Trade series (self-clinching, IFI-111 practice))
Thread size
Shank diameter (mm)
Length (mm)
Hole in sheet (mm)
Minimum sheet thickness (mm)
Maximum sheet hardness
Material
Installation
M3
4.20
3.30
4.22
0.8
HRB 80
Case-hardened steel
Press, squeeze
M4
5.40
3.80
5.42
0.8
HRB 80
Case-hardened steel
Press, squeeze
M5
6.35
4.20
6.38
1.0
HRB 80
Case-hardened steel
Press, squeeze
M6
7.95
4.80
7.98
1.0
HRB 80
Case-hardened steel
Press, squeeze
M8
9.55
5.70
9.58
1.5
HRB 80
Case-hardened steel
Press, squeeze
Materials & Grades
Select a material class to see the grades we supply it in. Each designation is listed with its ISO/EN, AISI/SAE, JIS and GB equivalents.
Sheet metal fabricationThreads in enclosure and chassis panels on the press line.
Electronics enclosuresCaptive threads for lids, brackets and PCB mounts.
Automotive & transportVibration-prone joints where the locking type is specified on the drawing.
Maintenance & MROReplacements matched to the existing bolt class, thread and finish.
Building servicesThreaded rod, channel and suspension assemblies.
Typical applications
limited by sheet HARDNESS, not sheet thickness
a permanent torque-resistant thread in sheet too thin to tap
installed by press, never by hammer
joints re-torqued at a service interval
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.
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.
This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.
01
Cold heading
Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.
Head dimensions and under-head radius checked at set-up and per shift.
02
Thread rolling
Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.
Go / no-go ring gauges to ISO 965 tolerance class 6g.
03
Heat treatment
Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.
Core hardness and tensile tested per lot to ISO 898-1.
04
Surface treatment
Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.
Coating thickness and neutral salt spray hours to ISO 9227.
Frequently Asked Questions
What corrosion resistance do Property Class 12.9 Steel Self-Clinching Press-Fit Nuts offer?
Property Class 12.9 Steel Self-Clinching Press-Fit Nuts provide requires plating or black-oxide protection with a service range of commonly limited to approx. +300 °C; confirm against the coating and the load.
When should I move from ISO 898-1 property class 12.9 to class 8.8 for Self-Clinching Press-Fit Nuts?
Step up to class 8.8 when the joint preload approaches the proof load of the current class. The higher class adds preload at the same diameter, often saving size and weight.
Is Property Class 12.9 Steel prone to hydrogen embrittlement?
Class 10.9 and above can be susceptible to hydrogen embrittlement when electroplated. Specify post-plating baking, or use mechanical-zinc / zinc-flake finishes which avoid the cathodic plating step.
Which finish is best for outdoor Self-Clinching Press-Fit Nuts?
For outdoor service in steel, hot-dip galvanizing gives the longest life; zinc-flake (Geomet/Delta-Tone family) gives a thinner film with excellent salt-spray performance; standard zinc plating is the lowest-cost option for general indoor / shielded outdoor use.
How do I request a quotation?
Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.
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