Gibraltar Z9131 Extra Thick Flat Washer 3/8 in 18-8 Ss

Product Description

The GIBRALTAR Z9131 is an extra thick flat washer designed for use with 3/8-inch fasteners in applications that require added load distribution and corrosion resistance. Constructed from Grade 18-8 stainless steel with a plain finish, this washer delivers reliable performance in wet, outdoor, and corrosive environments where standard-thickness washers may not provide sufficient bearing surface. With an inside diameter of 13/32 inches, an outside diameter of 13/16 inches, and a thickness of 1/8 inch, it offers a sturdy bearing surface suitable for demanding mechanical and structural fastening tasks. Plumbers, electricians, HVAC technicians, and general contractors install this type of hardware when securing equipment, panels, or structural components where corrosion resistance and load spreading are required.

This washer is suited for residential and commercial applications where 3/8-inch fasteners are used in environments exposed to moisture or mild chemicals. The extra thick profile makes it appropriate for use with soft substrates, oversized clearance holes, or applications requiring additional clamp load distribution. Common installation scenarios include equipment mounting, pipe support systems, electrical panel attachment, and general mechanical assemblies in both interior and exterior settings.

Key Features

• Extra thick profile at 1/8 inch provides greater load distribution than standard flat washers
• Grade 18-8 stainless steel construction resists corrosion in wet and outdoor environments
• Inside diameter of 13/32 inches fits standard 3/8-inch fasteners with appropriate clearance
• Outside diameter of 13/16 inches delivers a wide bearing surface for secure clamping
• Plain finish maintains material integrity without additional coating that could flake or peel
• Rockwell hardness rated C36-C42 for consistent mechanical performance under load

Compatibility

Designed for use with 3/8-inch screws and bolts in standard inch-measurement fastener assemblies requiring an extra thick flat washer.

Installation Notes

Install using standard hand tools appropriate for the fastener type. Ensure the mating fastener and nut are also stainless steel or a compatible alloy to prevent galvanic corrosion in wet environments. Do not overtighten fasteners, as stainless steel hardware is susceptible to galling. Follow applicable mechanical or structural codes for the specific application and trade discipline involved.