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6661521 — SEAT,HELICAL COMPRESSION SPRING

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

6661521: SEAT,HELICAL COMPRESSION SPRING.

SEAT,HELICAL COMPRESSION SPRING. Key specifications include material: STEEL CORROSION RESISTING, design_type: SOLID, end_diameter: 0.4900 INCHES NOMINAL IN, bore_diameter: 0.3770 INCHES NOMINAL IN, overall_height: 0.3130 INCHES NOMINAL IN, style_designator: SEAT. This part is cataloged in the U.S.

Government catalog under NSN 5340-00-118-3597, 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
6661521
NSN: 5340-00-118-3597
FSC: 5340 — Hardware, Commercial
CAGE: 09523 — PARKER-HANNIFIN CORPORATION DIV GAS TURBINE FUEL SYSTEMS (USA)
SPECIFICATIONS
materialSTEEL CORROSION RESISTING
design_typeSOLID
end_diameter0.4900 INCHES NOMINAL IN
bore_diameter0.3770 INCHES NOMINAL IN
overall_height0.3130 INCHES NOMINAL IN
style_designatorSEAT
first_step_length0.0950 INCHES NOMINAL IN
surface_treatmentPASSIVATE
counterbore_length0.0850 INCHES NOMINAL IN
first_step_diameter0.5430 INCHES NOMINAL IN
counterbore_diameter0.5015 INCHES NOMINAL IN
fsc_application_dataSEAT,HELICAL COMPRESSION SPRING,ENGINE,AIRCRAFT
NSN5340-00-118-3597
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: 6661521 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
•
FSC APPLICATION DATA: SEAT,HELICAL COMPRESSION SPRING,ENGINE,AIRCRAFT
•
FIRST STEP DIAMETER: 0.5430 INCHES NOMINAL IN
•
END DIAMETER: 0.4900 INCHES NOMINAL IN
•
DISTANCE FROM END TO FIRST STEP: 0.0840 INCHES NOMINAL IN
•
DESIGN TYPE: SOLID
•
STYLE DESIGNATOR: SEAT
•
COUNTERBORE LENGTH: 0.0850 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT0.3130 INCHES NOMINAL IN
FSC APPLICATION DATASEAT,HELICAL COMPRESSION SPRING,ENGINE,AIRCRAFT
FIRST STEP DIAMETER0.5430 INCHES NOMINAL IN
END DIAMETER0.4900 INCHES NOMINAL IN
DISTANCE FROM END TO FIRST STEP0.0840 INCHES NOMINAL IN
DESIGN TYPESOLID
STYLE DESIGNATORSEAT
COUNTERBORE LENGTH0.0850 INCHES NOMINAL IN
SECOND STEP DIAMETER0.7500 INCHES NOMINAL IN
COUNTERBORE DIAMETER0.5015 INCHES NOMINAL IN
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: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 6661521?
6661521 is a SEAT,HELICAL COMPRESSION SPRING.
What is the NSN for 6661521?
6661521 is cataloged in the U.S. Government catalog under NSN 5340-00-118-3597. 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.