JB NS4-6 3/8" SAE Flare Nut

The JB NS4-6 3/8" SAE Flare Nut is a heavy-duty, short type forged flare nut designed for the high-pressure demands of modern refrigeration and air conditioning systems. Unlike cheaper cast alternatives, this nut is forged from premium C360 brass (typically 65% copper and 35% zinc) to ensure superior tensile strength and eliminate the risk of stress cracks or porosity leaks. Built to strictly comply with SAE J513 standards, it provides a 100% reliable 45-degree metal-to-metal seal when paired with a properly flared tube. This HVAC flare nut is versatile enough for use with 3/8 inch OD copper tubing, as well as aluminum, brass, steel, and even specialized plastic tubing. Whether you are performing a mini-split installation or servicing industrial refrigerant lines, the forged brass construction provides the vibration resistance necessary for long-term field reliability under vacuum or pressures up to 5,000 PSI.

• Forged Brass Durability: Engineered from high-density forged brass to prevent "freeze" cracks and ensure structural integrity in high-vibration applications.
• Precise 45-Degree SAE Flare: Manufactured to SAE J513 refrigeration standards for a leak-proof mechanical joint without the need for thread sealants.
• Extreme Pressure Rating: Capable of handling operating pressures up to 5,000 PSI, making it ideal for high-pressure refrigerants like R410A and R32.
• ASTM Material Compliance: Uses C360/C370 premium brass to resist corrosion and ensure compatibility with standard 3/8" OD ACR tubing.

• Can this be used on R410A mini-split systems? Yes, forged flare nuts are specifically required for mini-splits to handle high operating pressures and prevent the nut from splitting over time.
• What is the difference between a short nut and a long nut? This short forged nut is designed for standard refrigeration and heating applications where space and weight are considerations; long nuts are typically reserved for extreme vibration scenarios.
• Does this fit 3/8" plumbing pipe? No. In the HVACR industry, 3/8" refers to the outside diameter (OD) of the tubing, not the nominal plumbing size. This is for 3/8" OD refrigeration copper.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.