Palnut Self Locking — Metric Sizes
What Are Palnut Self Locking?
Palnut self locking nuts are stamped, one-piece spring steel fasteners that use internal spring fingers to grip the thread of a bolt or stud, preventing loosening under vibration and shock loads. Unlike conventional hex nuts, Palnuts apply constant radial spring force against the thread flanks — maintaining clamp load without adhesives or additional locking hardware. They are widely used in automotive trim, home appliances, sheet metal assemblies, and any application where vibration resistance is required at low installation cost.
Key Features and Benefits
- Spring Locking Action: Internal fingers exert radial spring force on the thread, resisting loosening under vibration and shock without adhesives.
- One-Piece Construction: Stamped from a single piece of spring steel — no additional locking components required.
- Low Installation Force: Push-on design enables fast, tool-free installation ideal for high-volume assembly lines.
- Vibration Resistance: Maintains clamp load under cyclic loading, dynamic forces, and mechanical vibration.
- Cost-Effective Locking: Eliminates the need for thread-locking adhesives, split washers, or secondary locking hardware.
Materials and Finishes
- Spring Steel (Phosphate Coated): Standard material offering good corrosion resistance and consistent spring properties.
- Stainless Steel: For environments requiring higher corrosion resistance including wet and marine assemblies.
Standards Compliance
- DIN 6798 — Serrated lock washers (comparable locking principle)
- SAE J891 — Palnut push-on fasteners
Size Range and Availability
Available for M4 through M16 bolt sizes.
Frequently Asked Questions (FAQs)
1. What is a Palnut self locking fastener used for?
Palnuts are used wherever vibration or shock loads risk loosening conventional nuts — including automotive trim, appliance panels, sheet metal assemblies, and industrial equipment.
2. How does a Palnut prevent loosening?
Internal spring fingers exert continuous radial pressure on the thread flanks, resisting rotation under vibration and dynamic loading.
3. Can Palnuts be reused?
Palnuts are generally designed for single-use. Reuse may reduce locking effectiveness as spring fingers can lose preload after initial installation.
4. What material are Palnuts made from?
Our standard Palnuts are phosphate-coated spring steel. Stainless steel variants are available for corrosion-sensitive applications.
5. Are Palnuts suitable for outdoor use?
Stainless steel Palnuts are recommended for outdoor or humid environments. Phosphate-coated steel provides only moderate corrosion resistance.
6. What is the installation method for a Palnut?
Palnuts are typically push-on fasteners — thread them onto the bolt or stud by hand or with a light tool. The spring fingers engage automatically during installation.
7. What bolt sizes are Palnuts available for?
We stock Palnuts for M4 through M16 bolt sizes. Contact us for sizes outside this range.
8. Can Palnuts replace conventional hex nuts?
Palnuts are not intended to replace structural hex nuts. They are supplementary locking devices or low-torque primary fasteners for light assemblies.
9. Are Palnuts compatible with coated or painted surfaces?
Yes. Palnuts are widely used on painted and coated panels without damaging the surface when installed correctly.
10. Do Palnuts require any tools to install?
No. The push-on design allows tool-free installation, making them ideal for high-speed assembly environments.
