Property Class 8.8 Steel Aerospace Corner Self-Locking Nutplates are supplied to ISO 898-1 property class 8.8. Corrosion behaviour is requires plating (zinc) for corrosion 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 workhorse medium-carbon alloy class for structural joints.
- Grade
- ISO 898-1 property class 8.8
- Corrosion resistance
- Requires plating (zinc) for corrosion 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.
Aerospace Corner Self-Locking Nutplates manufactured in Property Class 8.8 Steel (ISO 898-1 property class 8.8) are dimensioned to MS21055 and NASM25027. 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 8.8 Steel for Aerospace Corner Self-Locking Nutplates
The workhorse medium-carbon alloy class for structural joints. For aerospace corner self-locking nutplates, this matters when requires plating (zinc) for corrosion protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 8.8 |
|---|
| Magnetic response | Magnetic |
|---|
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating (zinc) for corrosion protection |
|---|
Corrosion Behavior in Service
Carbon and alloy steel aerospace corner self-locking nutplates 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 Aerospace Corner Self-Locking Nutplates, class 10.9 or 12.9 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 Aerospace Corner Self-Locking Nutplates Available in Property Class 8.8 Steel
| Thread size | Overall length A (in) | Mounting-hole spacing J (in) | Width C (in) | Nut height (in) | Material options | Reference standard |
|---|
| 6-32 | 0.637 | 0.486 | 0.344 | 0.171 | cadmium-plated alloy steel or stainless steel | MS21055 and NASM25027 |
| 8-32 | 0.637~0.852 | 0.486~0.707 | 0.344~0.500 | 0.171~0.281 | cadmium-plated alloy steel or stainless steel | MS21055 and NASM25027 |
| 10-32 | 0.637~0.852 | 0.486~0.707 | 0.344~0.500 | 0.171~0.281 | cadmium-plated alloy steel or stainless steel | MS21055 and NASM25027 |
| 1/4-28 | 0.637~0.852 | 0.486~0.707 | 0.344~0.500 | 0.171~0.281 | cadmium-plated alloy steel or stainless steel | MS21055 and NASM25027 |
Applications & Industries
What Aerospace Corner Self-Locking Nutplates are specified for, industry by industry. Stocked from 6-32 to 1/4-28 (screw size).
Industries that specify Aerospace Corner Self-Locking Nutplates
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Avionics brackets
Serviceable hardware attached near a panel corner.
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Transport interiors
Compact self-locking threads behind trim and access panels.
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Aircraft skin panels
Corner-mounted self-locking nutplates in confined panel edges.
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Aerospace equipment bays
Fixed threaded points where a two-lug floating basket will not fit.
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Building services
Threaded rod, channel and suspension assemblies.
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Machine building & OEM
The clamping counter-face on studs and bolts throughout an assembly.
Typical applications
- holding a service screw captive at the back of a thin panel
- matching corner length, hole spacing, width and nut height to MS21055
- providing a fixed corner thread with self-locking torque
- placing a nutplate where edge access limits the mounting pattern
- joints re-torqued at a service interval
- completing a bolted joint on a stud, rod or bolt
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.
- Vibration
- Specified where cyclic load would loosen a plain nut or screw — rotating plant, rail, mobile equipment and anything that is not re-torqued in service.
- 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 substitute a floating two-lug nutplate when the corner pattern must stay fixed to the specified spacing.
Full application guide: where Aerospace Corner Self-Locking Nutplates are used, how to specify them, and the cases they are wrong for
