AN Hardware

AN Bolt Grip Length Chart (AN3–AN10)

Complete grip length reference for every AN bolt diameter. How to measure, common mistakes, and a full table cross-linking each dash number to in-stock parts.

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Spec Identification

NAS vs MS vs AN: How to Tell Them Apart

Head markings, material differences, tensile strength comparison. Know which spec you're holding before you order a replacement.

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Documentation

FAA 8130-3 Explained

What the airworthiness approval tag is, who can issue it, how to read it, and what "new surplus with 8130-3" means for legal installation.

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AN Hardware

AN3–AN10 Complete Sizing Reference

Master table: diameter, thread, grip lengths, and typical applications for every AN bolt size we stock.

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Installation

Castle Nut and Cotter Pin Pairing Guide

AN310 vs AN320, which cotter pin size matches, torque-and-back-off procedure, and FAA AC 43.13 references.

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Buying Guide

Surplus vs New Aircraft Hardware: The Honest Guide

When surplus is fine. When it isn't. What "new surplus" actually means, how 8130-3 protects the mechanic, and a real cost comparison.

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Spec Selection

AN vs MS vs NAS: Choosing the Right Spec

Why three standards exist, when each applies, and the substitution rules that keep your signoff clean. Includes FAA AC 43.13-1B references.

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Torque Reference

Aircraft Bolt Torque Specs: AN3–AN12 Chart

Dry and lubricated torque values from FAA AC 43.13-1B Table 7-1. Castle nut torque-and-advance procedure, calibration notes, and technique.

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Materials Reference

Fastener Materials: Cadmium, A286, Inconel, Titanium, CRES

Five material families, their strength ratings, temperature limits, and which zones they belong in. Material selection is a design decision, not an upgrade.

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Surface Finish Guide

Aircraft Fastener Finishes: Cadmium, Passivation, Anodize

AMS QQ-P-416, AMS 2700, MIL-A-8625 spec comparisons. Salt-spray ratings, galvanic compatibility, and hydrogen embrittlement risk explained.

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Thread Reference

Thread Classes & Fits: 3A/3B, UNF vs UNJF

Why aerospace uses Class 3A/3B only, the difference between UNF and UNJF root profiles, and the MIL-S-8879 (SAE AS8879) requirement for NAS hardware.

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Installation Guide

Drilled vs Undrilled Bolts: Castle Nuts & Safety Wire

When to use drilled shank vs drilled head bolts, how to install castle nuts per AC 43.13-1B, safety wire direction rules, and locking method selection.

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Procurement Guide

Surplus vs New: What the 8130-3 and CoC Actually Tell You

FAA traceability hierarchy — 8130-3, CoC, MTR — and how certified surplus is legally identical to new. Includes 30–60% cost advantage breakdown.

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