S-90089A320 0.312" ID x 0.438" OD Plastic Washers

Key Features & Benefits at a Glance

• Superior electrical insulation properties from hard fiber material, preventing current leakage in sensitive applications
• Excellent vibration dampening capability to maintain fastener integrity in high-movement environments
• Precise dimensional tolerances (0.312" ID, 0.438" OD) ensure perfect fit for 5/16" screws without binding or misalignment
• Temperature resistance up to 230°F maintains structural integrity in moderate heat applications
• RoHS 3 and REACH compliance guarantees environmental safety and regulatory acceptance for global supply chains
• Non-conductive and non-corrosive properties eliminate galvanic corrosion risks when used with metal fasteners
• Consistent thickness control (0.014-0.016") provides uniform load distribution and seating performance

Professional Applications & Engineering Value

These hard fiber flat washers deliver critical engineering solutions where electrical isolation and chemical resistance are paramount. The gray hard fiber construction provides excellent dielectric properties for electrical assemblies, preventing short circuits while offering superior resilience against oils and mild chemicals. With precise 0.312" ID dimensions engineered specifically for 5/16" screws, these washers eliminate installation issues common in electrical panels, machinery guards, and automotive components. The material's natural lubricity allows for smooth tightening without fiber shredding, while the controlled 0.014-0.016" thickness ensures consistent compression and reliable sealing in industrial applications where metal washers would create conductivity concerns.

Specification Summary & Compliance

Manufactured to precise inch system dimensions with 0.312" inner diameter and 0.438" outer diameter, these flat washers maintain tight thickness tolerances between 0.014-0.016" for uniform performance. The washers comply with RoHS 3 (2015/863/EU) standards and meet REACH (EC 1907/2006) requirements current through June 14, 2023, ensuring regulatory compliance for international industrial applications. Designed specifically for 5/16" screw sizes, these components operate effectively within their rated 230°F maximum temperature range while providing reliable non-metallic sealing and insulation properties.