Rivetking FBUP-4/P500 Blind Rivet Backup Washer Size 4 500 Pack

Product Description

The RIVETKING FBUP-4/P500 is a Size 4 round blind rivet backup washer designed to distribute load and prevent pull-through on blind rivet installations. Manufactured from stainless steel, this washer measures 0.125 inches inside diameter, 0.375 inches outside diameter, and 0.0625 inches thick. It is suited for use with 1/8-inch diameter blind rivets. The package contains 500 washers, making it a practical choice for production shops, field service teams, and maintenance contractors who go through fastener hardware at volume. Stainless steel construction provides corrosion resistance in wet or chemically exposed environments.

Blind rivet backup washers are used in applications where the substrate material is thin, soft, or prone to deformation under rivet head load. Typical scenarios include sheet metal fabrication, HVAC duct and panel assembly, electrical enclosure work, and plumbing fixture mounting. The washer seats against the blind side of the workpiece, spreading clamping force across a larger surface area. This prevents the rivet mandrel from pulling through materials that would otherwise tear or dimple under standard rivet head bearing loads.

Key Features

• Sized for 1/8-inch diameter blind rivets (Size Code 4)
• Stainless steel construction resists corrosion in wet and exposed environments
• 0.375-inch outside diameter spreads load across thin or soft substrates
• 0.0625-inch thickness provides a low-profile fit in tight assemblies
• 500-piece pack quantity reduces reorder frequency for high-volume work

Compatibility

Designed for use with Size 4 blind rivets with a 1/8-inch rivet diameter. Suitable as a backup washer in standard blind rivet installations across sheet metal, panel, and enclosure applications.

Installation Notes

Install these washers on the blind side of the workpiece before setting the rivet, ensuring the washer ID is aligned with the drilled hole. No special tools are required beyond standard rivet installation equipment. Inspect the substrate surface to confirm the washer seats flat before driving the rivet. Follow applicable fastener and sheet metal fabrication standards for the specific application.