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561-6404326-7 — SEAT,HELICAL COMPRESSION SPRING

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

561-6404326-7: SEAT,HELICAL COMPRESSION SPRING.

SEAT,HELICAL COMPRESSION SPRING. Key specifications include material: STEEL COMP 304, design_type: SOLID, end_diameter: 0.4690 INCHES NOMINAL IN, bore_diameter: 0.2810 INCHES NOMINAL IN, overall_height: 0.3800 INCHES NOMINAL IN, special_features: CENTER HOLE NOT COMPLETELY THRU ITEM; COUNTERSUNK 0.341 IN. BY 90 DEGREE.

IN. This part is cataloged in the U.S. Government catalog under NSN 5340-01-378-3993, 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
561-6404326-7
NSN: 5340-01-378-3993
FSC: 5340 — Hardware, Commercial
CAGE: 53711 — NAVAL SEA SYSTEMS COMMAND (USA)
SPECIFICATIONS
materialSTEEL COMP 304
design_typeSOLID
end_diameter0.4690 INCHES NOMINAL IN
bore_diameter0.2810 INCHES NOMINAL IN
overall_height0.3800 INCHES NOMINAL IN
special_featuresCENTER HOLE NOT COMPLETELY THRU ITEM; COUNTERSUNK 0.341 IN. BY 90 DEGREE. IN
style_designatorSEAT
first_step_diameter1.0000 INCHES NOMINAL IN
distance_from_end_to_first_step0.2600 INCHES NOMINAL IN
material_document_and_classificationQQ-S-766, CLASS 304, COND A, FINISH 1 FED SPEC SINGLE MATERIAL RESPONSE
NSN5340-01-378-3993
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: 561-6404326-7 MFR: OEM ⚠ VERIFY BEFORE ORDERING Wrong material = failure. Viton for oil/fuel, EPDM for water/steam, Buna-N for general purpose, Silicone for food-grade. Chemical incompatibility causes swelling, brittleness, or rapid degradation ✓ BROKER TIP Durometer (hardness) affects sealing pressure tolerance. Higher Shore A = harder = higher pressure. Standard durometer is 70A — verify if application requires different hardness PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
FIRST STEP DIAMETER: 1.0000 INCHES NOMINAL IN
•
END DIAMETER: 0.4690 INCHES NOMINAL IN
•
DISTANCE FROM END TO FIRST STEP: 0.2600 INCHES NOMINAL IN
•
DESIGN TYPE: SOLID
•
STYLE DESIGNATOR: SEAT
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-S-766, CLASS 304, COND A, FINISH 1 FED SPEC SINGLE MATERIAL RESPONSE
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT0.3800 INCHES NOMINAL IN
FIRST STEP DIAMETER1.0000 INCHES NOMINAL IN
END DIAMETER0.4690 INCHES NOMINAL IN
DISTANCE FROM END TO FIRST STEP0.2600 INCHES NOMINAL IN
DESIGN TYPESOLID
STYLE DESIGNATORSEAT
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-S-766, CLASS 304, COND A, FINISH 1 FED SPEC SINGLE MATERIAL RESPONSE
SPECIAL FEATURESCENTER HOLE NOT COMPLETELY THRU ITEM; COUNTERSUNK 0.341 IN. BY 90 DEGREE. IN
BORE DIAMETER0.2810 INCHES NOMINAL IN
MATERIALSTEEL COMP 304
OTHER ITEMS IN FSC 5340 — Hardware, Commercial
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5340-00-000-0068 5340-00-000-0132 5340-00-000-8150 5340-00-001-1251 5340-00-001-1264 5340-00-001-1265 5340-00-001-1266 5340-00-001-1275
SUBSTITUTES & CROSS-REFERENCES

No substitute or cross-reference records for this part.

LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Semi-active item — no replacement plannedNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 561-6404326-7?
561-6404326-7 is a SEAT,HELICAL COMPRESSION SPRING.
What is the NSN for 561-6404326-7?
561-6404326-7 is cataloged in the U.S. Government catalog under NSN 5340-01-378-3993. 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.