Which of the following describes the AN8-12 bolt dimension?

• A. 1/2 inch diameter, 1 1/4 inch length
• B. 1/4 inch diameter, 1 inch length
• C. 3/4 inch diameter, 2 inch length
• D. 1/2 inch diameter, 2 inch length

Answer: (A)

Bolts in the AN system are named with a diameter part and a length code. The diameter part is given in sixteenths of an inch: 8 × 1/16 inch equals 1/2 inch, so AN8 is a 1/2 inch diameter bolt. The dash number is a length code from a standard table; in this designation, 12 corresponds to a length of 1 1/4 inches. Therefore, AN8-12 describes a bolt that is 1/2 inch in diameter and 1 1/4 inches long. The other options would mismatch either the diameter (for example, a 1/4 inch diameter would be AN4) or the length code (a longer bolt would use a different dash value), so this combination best fits the AN8-12 specification.