Gibraltar Z8850 M10 Extra Thick Flat Washer Black Oxide

Product Description

The GIBRALTAR Z8850 is an extra thick flat washer engineered for M10 screw applications where standard washers lack the bearing surface or load distribution needed for demanding fastening work. Manufactured from 1010 case-hardened steel with a black oxide finish, it delivers surface hardness that resists wear under dynamic loading. The washer measures 10.5 mm inside diameter, 23 mm outside diameter, and 5 mm thick, providing a substantial clamping surface well beyond standard flat washer profiles. Machinists, millwrights, maintenance technicians, and fabricators reach for this part when assembly specs call for metric hardware with consistent dimensional tolerances and corrosion resistance.

This washer suits metric M10 fastener assemblies across industrial, commercial, and mechanical maintenance applications. It is commonly used in machinery assembly, structural connections, and equipment fabrication where a thick bearing surface is required to prevent fastener pull-through, distribute clamp load across softer base materials, or serve as a hardened backing element in bolted joints. The black oxide finish provides mild corrosion resistance and reduces surface galling during installation.

Key Features

• Extra thick 5 mm profile distributes clamp load across a wider bearing surface than standard flat washers
• Case-hardened 1010 steel construction resists deformation under high compressive loads
• Black oxide finish provides mild corrosion resistance and a low-reflectance appearance
• 10.5 mm inside diameter sized for M10 fasteners with consistent metric tolerances
• 23 mm outside diameter delivers broad load distribution for pull-through prevention
• Metric dimensioning per standard M10 hardware specifications

Compatibility

Designed for use with M10 metric screws and bolts in industrial, commercial, and mechanical assembly applications requiring an extra thick flat washer with a hardened steel bearing surface.

Installation Notes

Installation is performed by hand tools or standard wrenches as part of a bolted assembly. Ensure mating fastener is a true M10 metric specification before installation. Power down or de-energize any equipment before accessing fastener locations in live machinery. Do not substitute this washer in applications requiring a specific SAE or USS flat washer standard without confirming dimensional equivalence.