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Steel Adapter, 9/16-18 Male SAE O-Ring Boss (Straight Thread O-Ring) To 1/4-18 Male NPT, Straight

Alternate Part Numbers Alternate Part Number 6401-06-04, Alternate Part Number C1DY14, Alternate Part Number MI-00319283, Alternate Part Number MINO-00028F65391	Brand Brennan Industries Inc	Brand Brennan Industries	Pack Size 1.00	UOM EA	L 1.29	Supplier Part Number 6401-06-04-O	Thread 1 9/16-18	Thread 2 1/4-18	Thread Sealant No	Product Weight 0.00 lbs

Product Questions & Answers 2

Product Questions & Answers

Will this fitting work okay with standard NPT threads?

Question by: Tammy H on Aug 15, 2025, 12:50 PM

This adapter has a 1/4-18 Male NPT end, so it's designed to connect to standard female NPT threads of the same size.

Answer by: Customer Support on Aug 17, 2025, 8:33 AM

Got a hydraulic line coming off a pump with a 1/4 NPT port and I need to step it up to an ORB fitting on the valve block. This the right piece for that?

Question by: Duane H on Jan 2, 2026, 7:54 PM

That's exactly the situation this adapter is built for. One end is a 9/16-18 Male SAE O-Ring Boss and the other is 1/4-18 Male NPT, so you'd be connecting a standard NPT port on one side to an ORB port on the other. Just make sure the valve block port is a female ORB and the pump port is female NPT and you're in good shape.

Answer by: Customer Support on Jan 4, 2026, 6:54 AM

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