Hillman Fasteners 280307 5/8 Inch Flat Washer Uss Wide Pattern 25 Pack

Product Description

The HILLMAN FASTENERS 280307 is a 5/8-inch flat washer in a 25-pack format, manufactured to USS wide-pattern standards. Each washer is made from zinc-plated steel with a yellow dichromate finish, providing corrosion resistance suitable for general fastening applications in trade and construction environments. The wide-pattern USS profile distributes load across a broader surface area compared to SAE narrow-pattern washers, reducing the risk of fastener pull-through in softer substrates. Plumbers, electricians, HVAC technicians, and general contractors use flat washers like these daily in equipment mounting, pipe support, and structural fastening work.

These washers are suited for residential and light commercial applications wherever a 5/8-inch bolt or threaded rod requires a wide bearing surface. Common install scenarios include equipment pads, pipe hangers, panel mounting, and structural connections. The yellow dichromate coating adds a secondary layer of protection over the zinc plating, making these appropriate for mildly corrosive environments such as mechanical rooms and outdoor-adjacent installations. The 25-pack quantity is practical for service vans and job-site supply.

Key Features

• USS wide-pattern profile for increased load distribution compared to SAE flat washers
• Zinc-plated steel construction with yellow dichromate finish for corrosion resistance
• 5/8-inch nominal size fits standard 5/8-inch bolts and threaded rod
• 25-pack quantity for job-site and service-van stocking
• General-purpose fastening use across HVAC, plumbing, electrical, and construction trades

Compatibility

Designed as a standard USS wide-pattern flat washer for use with 5/8-inch diameter fasteners in general trade and construction applications.

Installation Notes

Flat washers are installed between the fastener head or nut and the mating surface prior to torquing. Ensure the washer seats flush with no debris underneath. In corrosive environments, confirm the dichromate-finished washer is compatible with the base material to avoid galvanic issues. No special tools are required beyond standard wrenches or sockets appropriate to the fastener being used.