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6565-21-125-5105 — SEAT,HELICAL COMPRESSION SPRING

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

6565-21-125-5105: SEAT,HELICAL COMPRESSION SPRING.

SEAT,HELICAL COMPRESSION SPRING. Key specifications include material: STEEL COMP 630, end_diameter: 0.4000 INCHES MINIMUM AND 0.4200 INCHES MAXIMUM IN, bore_diameter: 0.3120 INCHES MINIMUM AND 0.3140 INCHES MAXIMUM IN, overall_height: 0.2500 INCHES MINIMUM AND 0.2600 INCHES MAXIMUM IN, special_features: PASSIVATE SS8435, surface_treatment: PASSIVATE. This part is cataloged in the U.S.

Government catalog under NSN 5340-00-245-1872, 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
6565-21-125-5105
NSN: 5340-00-245-1872
FSC: 5340 — Hardware, Commercial
CAGE: 78286 — SIKORSKY AIRCRAFT CORPORATION DBA SIKORSKY AIRCRAFT CORP (USA)
SPECIFICATIONS
materialSTEEL COMP 630
end_diameter0.4000 INCHES MINIMUM AND 0.4200 INCHES MAXIMUM IN
bore_diameter0.3120 INCHES MINIMUM AND 0.3140 INCHES MAXIMUM IN
overall_height0.2500 INCHES MINIMUM AND 0.2600 INCHES MAXIMUM IN
special_featuresPASSIVATE SS8435
surface_treatmentPASSIVATE
first_step_diameter0.4350 INCHES MINIMUM AND 0.4370 INCHES MAXIMUM IN
countersink_diameter0.0100 INCHES MINIMUM AND 0.0200 INCHES MAXIMUM IN
countersink_angle_in_deg45.0
distance_from_end_to_first_step0.0900 INCHES MINIMUM AND 0.1100 INCHES MAXIMUM IN
material_document_and_classificationAMS 5643 ASSN STD SINGLE MATERIAL RESPONSE
NSN5340-00-245-1872
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: 6565-21-125-5105 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
•
COUNTERSINK ANGLE IN DEG: 45.0
•
FIRST STEP DIAMETER: 0.4350 INCHES MINIMUM AND 0.4370 INCHES MAXIMUM IN
•
END DIAMETER: 0.4000 INCHES MINIMUM AND 0.4200 INCHES MAXIMUM IN
•
COUNTERSINK DIAMETER: 0.0100 INCHES MINIMUM AND 0.0200 INCHES MAXIMUM IN
•
DISTANCE FROM END TO FIRST STEP: 0.0900 INCHES MINIMUM AND 0.1100 INCHES MAXIMUM IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 5643 ASSN STD SINGLE MATERIAL RESPONSE
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT0.2500 INCHES MINIMUM AND 0.2600 INCHES MAXIMUM IN
COUNTERSINK ANGLE IN DEG45.0
FIRST STEP DIAMETER0.4350 INCHES MINIMUM AND 0.4370 INCHES MAXIMUM IN
END DIAMETER0.4000 INCHES MINIMUM AND 0.4200 INCHES MAXIMUM IN
COUNTERSINK DIAMETER0.0100 INCHES MINIMUM AND 0.0200 INCHES MAXIMUM IN
DISTANCE FROM END TO FIRST STEP0.0900 INCHES MINIMUM AND 0.1100 INCHES MAXIMUM IN
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 5643 ASSN STD SINGLE MATERIAL RESPONSE
SPECIAL FEATURESPASSIVATE SS8435
SURFACE TREATMENTPASSIVATE
BORE DIAMETER0.3120 INCHES MINIMUM AND 0.3140 INCHES MAXIMUM 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 6565-21-125-5105?
6565-21-125-5105 is a SEAT,HELICAL COMPRESSION SPRING.
What is the NSN for 6565-21-125-5105?
6565-21-125-5105 is cataloged in the U.S. Government catalog under NSN 5340-00-245-1872. 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.