BOLT (P/N an4-31a) - New Surplus

The AN4-31A is a 1/4-inch hex head airframe bolt with 1/4-28 UNF-3A threading and an undrilled shank. Constructed from alloy steel, this fastener conforms to AN/NASM4 standards for aerospace applications. Used in structural airframe joints where 1/4-inch bolts are specified, it provides reliable fastening in primary and secondary structures.

Installation requires proper grip length selection and torque application per aircraft maintenance manuals and FAA AC 43.13-1B guidance. The undrilled design (-A suffix) makes it suitable for standard fastening without castellated nut requirements.

What is the BOLT (P/N an4-31a)?

The AN4-31A is a 1/4-inch hex head airframe bolt with 1/4-28 UNF-3A threading and an undrilled shank. Constructed from alloy steel, this fastener conforms to AN/NASM4 standards for aerospace applications.

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

Aircraft hardware is manufactured to military and aviation specifications. The BOLT 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 an4-31a 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 an4-31a.

Can I order the an4-31a in custom quantities?

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