Fine-Thread Hex Nuts, Style 2 manufactured in Property Class 12.9 Steel (ISO 898-1 property class 12.9) are dimensioned to ISO 8674. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose Property Class 12.9 Steel for Fine-Thread Hex Nuts, Style 2
The highest common strength class, for high-load machine assembly. For fine-thread hex nuts, style 2, 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 |
Corrosion Behavior in Service
Carbon and alloy steel fine-thread hex nuts, style 2 require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Comparable Grades
For Fine-Thread Hex Nuts, Style 2, 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 Fine-Thread Hex Nuts, Style 2 Available in Property Class 12.9 Steel
| Size | Pitch P (mm) | c (mm) | damax (mm) | dw (mm) | Width across corners e (mm) | Nut height m (mm) | mw (mm) | Width across flats s (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|
| M8x1 | 1.0 | 0.3 | 8.75 | 11.63 | 14.38 | 7.5 | 5.71 | 13.0 | ISO 8674 |
| M10x1 | 1.0 | 0.3 | 10.8 | 14.63 | 17.77 | 9.3 | 7.15 | 16.0 | ISO 8674 |
| M10x1.25 | 1.25 | 0.3 | 10.8 | 14.63 | 17.77 | 9.3 | 7.15 | 16.0 | ISO 8674 |
| M12x1.5 | 1.5 | 0.3 | 13.0 | 16.63 | 20.3 | 12.0 | 9.62 | 18.0 | ISO 8674 |
| M12x1.25 | 1.25 | 0.3 | 13.0 | 16.63 | 20.3 | 12.0 | 9.62 | 18.0 | ISO 8674 |
| (M14x1.5) | 1.5 | 0.3 | 15.1 | 19.64 | 23.36 | 14.1 | 10.72 | 21.0 | ISO 8674 |
| M16x1.5 | 1.5 | 0.4 | 17.3 | 22.49 | 26.75 | 16.4 | 12.56 | 24.0 | ISO 8674 |
| M18x1.5 | 1.5 | 0.4 | 19.5 | 24.85 | 29.56 | 17.6 | 13.52 | 27.0 | ISO 8674 |
| M20x1.5 | 1.5 | 0.4 | 21.6 | 27.7 | 32.95 | 20.3 | 15.2 | 30.0 | ISO 8674 |
| (M20x2) | 2.0 | 0.4 | 21.6 | 27.7 | 32.95 | 20.3 | 15.2 | 30.0 | ISO 8674 |
| (M22x1.5) | 1.5 | 0.4 | 23.7 | 31.35 | 37.29 | 21.8 | 16.4 | 34.0 | ISO 8674 |
| M24x2 | 2.0 | 0.4 | 25.9 | 33.25 | 39.5 | 23.9 | 18.08 | 36.0 | ISO 8674 |
| (M27x2) | 2.0 | 0.4 | 29.1 | 38.0 | 45.2 | 26.7 | 20.32 | 41.0 | ISO 8674 |
| M30x2 | 2.0 | 0.4 | 32.4 | 42.75 | 50.85 | 28.6 | 21.85 | 46.0 | ISO 8674 |
| (M33x2) | 2.0 | 0.4 | 35.6 | 46.55 | 55.37 | 32.5 | 24.72 | 50.0 | ISO 8674 |
| M36x3 | 3.0 | 0.4 | 38.9 | 51.11 | 60.79 | 34.7 | 26.48 | 55.0 | ISO 8674 |
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. Thread, height, across-flats, property class, locking feature and flange form can all be varied, including thread sizes the standard series does not run to. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

