Nas1830 [hot]

Here’s a technical write-up on NAS1830 , based on available data and typical applications in aerospace fastening systems.

Technical Write-Up: NAS1830 – Blind Rivet, Protruding Head, Self-Plugging 1. Overview NAS1830 is a performance specification under the National Aerospace Standard (NAS) for a blind, self-plugging mechanical lock rivet with a protruding head . It is designed for high-strength, fatigue-resistant applications where only one side of the structure is accessible. The rivet provides a positive mechanical lock between the pin and collar, ensuring consistent clamp-up and vibration resistance. 2. Key Characteristics | Feature | Details | |------------------------|-------------------------------------------------------------------------| | Head Style | Protruding (round, universal) – not countersunk | | Installation | Blind (access from one side only) | | Locking Mechanism | Mechanical lock (swaged collar into pin grooves) | | Material (Typical) | A-286 CRES (corrosion-resistant steel), Inconel 718, or Monel (pin) | | Grip Range | Specified in dash numbers (e.g., -04, -05, -06) | | Shear Strength | High (typically 95–120 ksi ultimate shear, alloy-dependent) | | Fatigue Rating | Excellent (mechanical lock eliminates stem push-out) | 3. Comparison with Common Blind Rivets | Property | NAS1830 (Mechanical Lock) | NAS1398/HC (Pull-Type, Break Stem) | |------------------|----------------------------|--------------------------------------| | Stem Retention | Yes – locked in place | No – stem broken off | | Fluid Seal | Good (with optional sealant)| Fair | | Vibration Resistance | High | Moderate | | Installation Tooling | Hydraulic/pneumatic pull-swag | Hand or power pull-type | | Reusability | No | No | 4. Typical Applications

Aircraft secondary structures (fairings, access panels, non-pressurized areas) Engine nacelle components Fuel tank access covers (when used with wet installation sealant) Helicopter airframes Military ground vehicle armor attachments (where blind installation is needed)

5. Installation Process (Simplified)

Drill & deburr hole to specified size (e.g., 0.1890–0.1915 in. for a #10 rivet). Insert rivet through the aligned sheets. Place installation tool over the stem. Apply pull force – tool jaws grip stem and pull while an anvil swages the collar into the stem’s locking grooves. Stem fractures at a breakneck groove below the flush position , leaving the mechanical lock engaged. Inspect for flush stem break (no protrusion beyond head) and head seating.

6. Advantages & Limitations Advantages:

No loose stem fragments (FOD risk reduced) Consistent preload due to mechanical lock Suitable for high-vibration environments Wide material compatibility (CRES to aluminum, titanium, composites) nas1830

Limitations:

Requires specialized pull-swag tooling (e.g., Huck 940 or equivalent) Higher installed cost vs. break-stem rivets Protruding head may not be aerodynamic (requires clearance or subsequent fairing)

7. Ordering Example A typical NAS1830 part number breakdown: NAS1830-4-5 Here’s a technical write-up on NAS1830 , based

NAS1830 – Specification 4 – Dash number (diameter: #4 = 0.125 in. nominal) 5 – Grip length code (e.g., 0.250–0.312 in. grip range)

Grip codes vary by manufacturer; always reference the latest NAS1830 procurement specification or manufacturer data sheet (e.g., Cherry Aerospace, Lisi Aerospace).