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GB521 — CUP,OIL,LUBRICATING

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

GB521: CUP,OIL,LUBRICATING.

The CUP,OIL,LUBRICATING is a the manufacturer industrial component. Key specifications include height: 0.323 INCHES NOMINAL IN, material: STEEL OVERALL, shank_length: 0.250 INCHES NOMINAL IN, shank_diameter: 0.251 INCHES NOMINAL IN, style_designator: STRAIGHT, W/BALL CHECK, W/SHOULDER, assembly_clearance_radius: 0.142 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-325-3169, 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
GB521
NSN: 4730-00-325-3169
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 24981 — APACHE CORP GITS BROS MFG CO (USA)
SPECIFICATIONS
height0.323 INCHES NOMINAL IN
materialSTEEL OVERALL
shank_length0.250 INCHES NOMINAL IN
shank_diameter0.251 INCHES NOMINAL IN
style_designatorSTRAIGHT, W/BALL CHECK, W/SHOULDER
assembly_clearance_radius0.142 INCHES NOMINAL IN
NSN4730-00-325-3169
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: GB521 · 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
•
SHANK DIAMETER: 0.251 INCHES NOMINAL IN
•
ASSEMBLY CLEARANCE RADIUS: 0.142 INCHES NOMINAL IN
•
SHANK LENGTH: 0.250 INCHES NOMINAL IN
•
STYLE DESIGNATOR: STRAIGHT, W/BALL CHECK, W/SHOULDER
•
HEIGHT: 0.323 INCHES NOMINAL IN
•
MATERIAL: STEEL OVERALL
TECHNICAL CHARACTERISTICS
SHANK DIAMETER0.251 INCHES NOMINAL IN
ASSEMBLY CLEARANCE RADIUS0.142 INCHES NOMINAL IN
SHANK LENGTH0.250 INCHES NOMINAL IN
STYLE DESIGNATORSTRAIGHT, W/BALL CHECK, W/SHOULDER
HEIGHT0.323 INCHES NOMINAL IN
MATERIALSTEEL OVERALL
SUBSTITUTES & CROSS-REFERENCES 1
122220Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is GB521?
GB521 is a CUP,OIL,LUBRICATING.
What parts can replace GB521?
There is 1 known substitute for GB521: 122220. Substitute compatibility should be verified for your specific system.
What is the NSN for GB521?
GB521 is cataloged in the U.S. Government catalog under NSN 4730-00-325-3169. 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.