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4BU — NIPPLE,TUBE

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

4BU: NIPPLE,TUBE.

The NIPPLE,TUBE is a the manufacturer industrial component. Key specifications include material: COPPER ALLOY OVERALL, seat_angle: 20.0 DEGREES ALL ENDS, thread_class: 2A CENTER BULKHEAD A, connection_style: FLARELESS (TUBE) ALL ENDS, style_designator: FLARELESS W/ OFFSET WRENCHING FACILITY, nominal_thread_size: 0.438 INCHES CENTER BULKHEAD IN. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-061-6912, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
4BU
NSN: 4730-00-061-6912
NIINs: 000616912, 013474689
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 28968 — CIRCOR INSTRUMENTATION TECHNOLOGIES, INC. DBA HOKE GYROLOK (USA)
SPECIFICATIONS
materialCOPPER ALLOY OVERALL
seat_angle20.0 DEGREES ALL ENDS
thread_class2A CENTER BULKHEAD A
connection_styleFLARELESS (TUBE) ALL ENDS
style_designatorFLARELESS W/ OFFSET WRENCHING FACILITY
nominal_thread_size0.438 INCHES CENTER BULKHEAD IN
nominal_overall_length2.270 INCHES IN
thread_series_designatorUNF CENTER BULKHEAD
furnished_items_and_quantity4 FERRULE SLEEVE AND 2 TUBE COUPLING NUT AND 1 LOCKNUT
nominal_outside_diameter_tube_accommodated0.250 INCHES ALL ENDS IN
NSN4730-00-061-6912
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: 4BU · OEM ⚠ VERIFY BEFORE ORDERING NPT ≠ BSPT — tapered threads look identical but are NOT interchangeable. Wrong thread = leak. JIC (37°) ≠ AN (37°) ≠ SAE 45° — flare angles must match exactly. Measure thread pitch with gauge — visual identification is unreliable ✓ BROKER TIP Always use thread sealant (PTFE tape or pipe compound) on tapered threads (NPT/BSPT). JIC/AN flare fittings seal metal-to-metal — never use tape on flare connections PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
FURNISHED ITEMS AND QUANTITY: 4 FERRULE SLEEVE AND 2 TUBE COUPLING NUT AND 1 LOCKNUT
•
CONNECTION STYLE: FLARELESS (TUBE) ALL ENDS
•
NOMINAL OVERALL LENGTH: 2.270 INCHES IN
•
STYLE DESIGNATOR: FLARELESS W/ OFFSET WRENCHING FACILITY
•
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED: 0.250 INCHES ALL ENDS IN
•
NOMINAL THREAD SIZE: 0.438 INCHES CENTER BULKHEAD IN
•
SEAT ANGLE: 20.0 DEGREES ALL ENDS
TECHNICAL CHARACTERISTICS
FURNISHED ITEMS AND QUANTITY4 FERRULE SLEEVE AND 2 TUBE COUPLING NUT AND 1 LOCKNUT
CONNECTION STYLEFLARELESS (TUBE) ALL ENDS
NOMINAL OVERALL LENGTH2.270 INCHES IN
STYLE DESIGNATORFLARELESS W/ OFFSET WRENCHING FACILITY
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED0.250 INCHES ALL ENDS IN
NOMINAL THREAD SIZE0.438 INCHES CENTER BULKHEAD IN
NOMINAL THREAD SIZE0.438 INCHES ALL ENDS IN
SEAT ANGLE20.0 DEGREES ALL ENDS
THREAD CLASS2A CENTER BULKHEAD A
THREAD CLASS2A ALL ENDS A
SUBSTITUTES & CROSS-REFERENCES 3
4-4 WBZ-BSame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
100116-003Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
R BC 4Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusCancelled· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 4BU?
4BU is a NIPPLE,TUBE.
What parts can replace 4BU?
There are 3 known substitutes for 4BU: 4-4 WBZ-B, 100116-003, R BC 4. Substitute compatibility should be verified for your specific system.
What is the NSN for 4BU?
4BU is cataloged in the U.S. Government catalog under NSN 4730-00-061-6912. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.