BOLT, MACHINE (P/N an4-21) - New Surplus

The AN4-21 is a 1/4-inch hex head machine bolt conforming to AN/NASM4 specifications. Manufactured from heat-treated alloy steel, this fastener features a 1/4-28 UNF thread and -21 length designation for aircraft structural applications. Used to secure airframe brackets, fittings, and components under tension or shear loads.

Installation requires proper grip length selection and torque application per FAA AC 43.13-1B standards and aircraft maintenance documentation. Suitable for general aviation and commercial aircraft assembly and repair.

What is the BOLT, MACHINE (P/N an4-21)?

The AN4-21 is a 1/4-inch hex head machine bolt conforming to AN/NASM4 specifications. Manufactured from heat-treated alloy steel, this fastener features a 1/4-28 UNF thread and -21 length designation for aircraft structural applications.

What conditions is the an4-21 available in?

The an4-21 is currently available in the following conditions: New Surplus. Each condition reflects the part's maintenance history and certification status per FAA standards.

How do I get pricing for the an4-21?

The an4-21 requires a custom quote. Submit a Request for Quote (RFQ) through our website or call our sales team at (904) 998-9101 for immediate pricing assistance.

Do you offer expedited shipping for the an4-21?

Yes, we offer same-day processing on in-stock items and provide 24/7 AOG (Aircraft on Ground) support for urgent needs. Standard, expedited, and overnight shipping options are available.