A bolt head marked with an X inside a triangle is classified as which type?

A bolt head marked with an X inside a triangle is classified as which type?

• A. NAS Standard Aircraft Bolt
• B. NAS Close Tolerance Bolt
• C. AN Corrosion-Resistant Steel Bolt
• D. AN Standard Bolt

Answer: (B)

Bolt head markings convey the standard family and the tolerance class of the fastener. The symbol with an X inside a triangle identifies a NAS Close Tolerance Bolt. That marking is used to designate tighter dimensional limits than ordinary NAS bolts, which is important in assemblies where precise fit and alignment are critical. Explainings the context helps: NAS bolts are a family used in aircraft manufacturing, and the presence of a close-tolerance symbol tells you immediately that this bolt is intended for applications requiring tighter control over length, shank diameter, and other dimensions. The other options refer to different families or tolerance levels and would carry different markings or none of this symbol at all, so they aren’t indicated by the X-in-triangle mark.

Bolt head markings convey the standard family and the tolerance class of the fastener. The symbol with an X inside a triangle identifies a NAS Close Tolerance Bolt. That marking is used to designate tighter dimensional limits than ordinary NAS bolts, which is important in assemblies where precise fit and alignment are critical.

Explainings the context helps: NAS bolts are a family used in aircraft manufacturing, and the presence of a close-tolerance symbol tells you immediately that this bolt is intended for applications requiring tighter control over length, shank diameter, and other dimensions. The other options refer to different families or tolerance levels and would carry different markings or none of this symbol at all, so they aren’t indicated by the X-in-triangle mark.