Gibraltar Z8956H Square Flat Washer 5/8 in Bolt Steel

Product Description

The GIBRALTAR Z8956H is a square flat washer made from steel with a black oxide finish, designed for use with 5/8 inch bolts. It measures 2 inches square with an inside diameter of 11/16 inches and a thickness of 1/4 inch. The black oxide finish provides a degree of corrosion resistance and reduces light reflection in finished assemblies. This washer is used to distribute load across a larger surface area at a bolt or fastener connection point, reducing the risk of pull-through or surface damage in structural and mechanical applications. It is installed by electricians, plumbers, HVAC technicians, and general contractors wherever a square bearing surface is required.

This washer is suited for residential and commercial construction, mechanical equipment mounting, electrical panel and conduit support work, and general structural fastening applications. Its square geometry provides a larger bearing surface than a standard round washer of comparable inside diameter, making it a common choice for wood framing connections, unistrut channel work, and equipment pad anchor bolt installations. Weighing 0.05 pounds, it is a single-piece hardware item sold individually.

Key Features

• Square flat profile provides increased load distribution compared to round washers of similar bore
• Black oxide finish reduces surface corrosion and light reflection
• 11/16 inch inside diameter sized for 5/8 inch bolts
• 1/4 inch thickness supports use in high-load structural connections
• Steel construction compatible with standard fastener torque requirements

Compatibility

Designed as a standard square flat washer for use with 5/8 inch diameter bolts in structural, mechanical, and trade installation applications.

Installation Notes

Install with standard wrenches or impact drivers appropriate for the fastener size. Ensure mating surfaces are clean and free of debris before seating the washer. Black oxide parts should not be used as the sole corrosion barrier in continuously wet or outdoor exposed environments without additional protection. Follow applicable codes such as NEC or IBC for fastener and hardware requirements in electrical or structural installations.