WASHER, 4-40 UNC SINGLE COIL (P/N sp58a) - New Surplus

The sp58a is a steel single-coil lock washer sized for #4-40 UNC fasteners. This helical spring washer sits beneath screw heads or nuts to prevent loosening caused by vibration and thermal cycling. Commonly installed in avionics equipment mounts, instrument panel assemblies, and other vibration-sensitive aircraft structures.

The washer conforms to MS35338 specifications and ASME B18.21.1 standards. Install per aircraft maintenance manual torque guidance, placing the washer between the fastener and component surface to maintain secure connections during flight operations.

What is the WASHER, 4-40 UNC SINGLE COIL (P/N sp58a)?

The sp58a is a steel single-coil lock washer sized for #4-40 UNC fasteners. This helical spring washer sits beneath screw heads or nuts to prevent loosening caused by vibration and thermal cycling.

Does the sp58a meet AN/MS/NAS aviation specifications?

Aircraft hardware is manufactured to military and aviation specifications. The WASHER, 4-40 UNC SINGLE COIL conforms to its applicable AN (Air Force-Navy), MS (Military Standard), or NAS (National Aerospace Standard) specification. Contact us for specific specification details.

What material is the sp58a manufactured from?

Aviation hardware is available in various materials including cadmium-plated steel, stainless steel, aluminum alloy, and titanium depending on the application. Contact us for material certification and specifications for the sp58a.

Can I order the sp58a in custom quantities?

Yes, we sell hardware in various quantities from single units to bulk lots. The WASHER, 4-40 UNC SINGLE COIL is available in: New Surplus. Submit an RFQ for volume pricing or call (904) 998-9101 for quantity availability.