What type of coupling nut should be selected for 1/2 inch aluminum oil lines using flared tube ends?

• A. AN-811-8
• B. AN-818-8
• C. AN-820-8
• D. AN-814-8

Answer: (B)

The selection of the coupling nut for 1/2 inch aluminum oil lines with flared tube ends is essential for ensuring effective and leak-free connections. The correct choice, AN-818-8, is specifically designed for use with flared fittings, which is what you need for aluminum oil lines.

The AN-818-8 coupling nut is a hex-style nut that is utilized in conjunction with flared fittings to create a secure, leak-proof connection. Its design allows it to effectively compress the flared end of the tubing against the mating surface of the fitting, thus achieving a reliable seal that is crucial for fluid transfer applications.

Understanding your application's requirements, such as being used with flared tube ends, is key. This coupling nut is ideal because it is tailored to work with the AN standard flared fittings that are common in aviation and automotive fluid systems. The other options either don't match the flared application, or are designed for different configurations or pipe sizes, making them unsuitable for this specific task.