Midland Industries 640186 Straight Adapter Orb X Nptf Steel

Product Description

The MIDLAND INDUSTRIES 640186 is a straight hydraulic adapter that connects a 1/2-inch Male O-Ring Boss (ORB) port to a 3/8-inch Male NPTF fitting. Machined from steel, it is rated for continuous service up to 3600 psi and 375 degrees F. The ORB end seats against a flat surface with an O-ring for a leak-resistant seal, while the NPTF thread provides a dry-seal mechanical connection on the mating port. Thread sizes are 3/4-16 on the ORB end and 3/8-18 on the NPTF end. This adapter is installed by hydraulic technicians, fluid power mechanics, and plumbers working on high-pressure steel line assemblies.

The 640186 is suited for hydraulic systems and fluid power circuits where a transition between an O-Ring Boss port and a male NPTF connection is required. Typical applications include hydraulic manifolds, cylinders, pumps, and valves found in industrial and mobile equipment. Its compact dimensions make it practical in tight plumbing runs where space is limited.

Key Features

• 3600 psi maximum working pressure for high-pressure hydraulic service
• 375 degrees F maximum operating temperature
• 1/2-inch Male O-Ring Boss (3/4-16 thread) on one end for leak-resistant O-ring face seal
• 3/8-inch Male NPTF (3/8-18 thread) on opposite end for dry-seal pipe thread connection
• Steel construction for durability in hydraulic line applications
• Straight adapter configuration simplifies in-line port transitions

Compatibility

Designed as an OEM-style hydraulic fitting for systems using 1/2-inch Male O-Ring Boss ports and 3/8-inch Male NPTF connections in steel pipe adapter configurations. Part of the 6401 Series Male O-Ring to MNPT product family.

Installation Notes

Installation should be performed by a qualified hydraulic technician or fluid power mechanic. Depressurize and isolate the hydraulic circuit completely before removing or installing any fittings. Apply thread sealant to the NPTF end as required and verify the O-ring is properly seated and undamaged before torquing the ORB end. Do not overtighten; follow system component torque guidelines for the port size and material.