BOLT, HEX, MACHINE (P/N an4-31) - New Surplus

The AN4-31 is a 1/4-inch hex head machine bolt with 1/4-28 UNF-3A threads, manufactured from alloy steel per AN-series specifications. This fastener secures structural and mechanical assemblies in aircraft applications, including landing gear torque link assemblies. Length is measured from under the bolt head per standard AN conventions.

Installation requires matching the correct grip length to application requirements and applying torque per FAA AC 43.13-1B guidance. Verify part eligibility in the aircraft Illustrated Parts Catalog before use.

What is the BOLT, HEX, MACHINE (P/N an4-31)?

The AN4-31 is a 1/4-inch hex head machine bolt with 1/4-28 UNF-3A threads, manufactured from alloy steel per AN-series specifications. This fastener secures structural and mechanical assemblies in aircraft applications, including landing gear torque link assemblies.

Does the an4-31 meet AN/MS/NAS aviation specifications?

Aircraft hardware is manufactured to military and aviation specifications. The BOLT, HEX, MACHINE 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 an4-31 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 an4-31.

Can I order the an4-31 in custom quantities?

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