Steel Adapter, 1/2-14 Female NPT Swivel To 9/16-18 Male SAE O-Ring Boss (Straight Thread O-Ring), Straight

Manufactured from high-quality steel, this adapter is designed for demanding environments and should provide robust performance under varying pressure conditions.

Yeah, that's exactly the kind of transition this fitting is built for. One end threads into your 9/16-18 male SAE O-Ring Boss port, and the other side accepts a 1/2-14 female NPT swivel connection. The O-Ring Boss end seals against the port face with an o-ring rather than relying on thread sealant, so you get a clean metal-to-metal style seal without tape or compound on that side. The swivel on the NPT end gives you a little rotational freedom when you're tightening things up, which helps a lot when you're working in a tight spot and can't easily spin the line itself.