ADAPTER 5/16MB X 1/8 MP

Description & Features

Manufactured from straight steel, this Male SAE O-Ring Boss to Male NPTF adapter provides a reliable threaded transition between two common hydraulic fitting standards. The ADAPTER 5/16MB X 1/8 MP features a 5/16 Male SAE O-Ring Boss (1/2-20, per SAE J514) on one end and a 1/8-27 Male NPTF thread (per SAE J476) on the other, with an NBR O-ring seal that helps maintain a secure, leak-resistant connection at the SAE ORB port.

At an overall length of 1.050 inches, this compact straight adapter is suited for tight-clearance installations where a direct port-to-port connection is needed between ORB and NPTF threaded components. Manufactured by Brennan Industries under their 6401-O series, it carries a Proposition 65 warning for California residents.

SKU: 6401-05-02-O

Supplier Part Number (MPN): 6401-05-02-O

Alternate Part Numbers: C1EK72

Specifications

Connection Size 1
5/16 in
Connection Size 2
1/8 in
Connection Type
Male SAE ORB, MNPT
Connection Type 1
Male SAE ORB
Connection Type 2
MNPTF
Dimension Standards
SAE J1926, SAE J476, SAE J514
Dimensions
1.07 in L
Finish
Trivalent Zinc-Plated
Fitting Type
Adapter
Hex Size
5/8 in
Material
Steel
Material Construction
12L14/C1045 Steel
Maximum Operating Pressure
6000 psi
Operating Temperature
-40 to 250 deg F
Seal Material
NBR
Series
6401-O Series
Thread 2 Drill Dimensions
0.188 in
Thread B1 Drill Dimensions
0.234 in
Thread Size
1/2-20 x 1/8-27

Product Questions & Answers (1)

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Question by: Lynn H on Jan 27, 2026, 8:49 AM
So, this here adapter, it's got different threads on each end, right? What kinda threads are we talkin' about?
Answer by: Customer Support on Jan 28, 2026, 4:30 PM
You're right, it does have different threads. One end is a 5/16 Male SAE O-Ring Boss, and the other is a 1/8-27 Male NPTF thread.

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