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491691 — SEAT,HELICAL COMPRESSION SPRING

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

491691: SEAT,HELICAL COMPRESSION SPRING.

SEAT,HELICAL COMPRESSION SPRING. Key specifications include material: STEEL, design_type: SOLID, end_diameter: 0.3900 INCHES MINIMUM AND 0.4100 INCHES MAXIMUM IN, bore_diameter: 0.2490 INCHES MINIMUM AND 0.2510 INCHES MAXIMUM IN, overall_height: 0.2600 INCHES NOMINAL IN, style_designator: SEAT. This part is cataloged in the U.S.

Government catalog under NSN 5340-00-914-5394, 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
491691
NSN: 5340-00-914-5394
FSC: 5340 — Hardware, Commercial
CAGE: 77445 — RTX CORPORATION DBA PRATT & WHITNEY DIV PRATT &WHITNEY (USA)
SPECIFICATIONS
materialSTEEL
design_typeSOLID
end_diameter0.3900 INCHES MINIMUM AND 0.4100 INCHES MAXIMUM IN
bore_diameter0.2490 INCHES MINIMUM AND 0.2510 INCHES MAXIMUM IN
overall_height0.2600 INCHES NOMINAL IN
style_designatorSEAT
first_step_length0.0700 INCHES NOMINAL IN
surface_treatmentPASSIVATE
counterbore_length0.1200 INCHES NOMINAL IN
first_step_diameter1.0900 INCHES NOMINAL IN
second_end_diameter0.8400 INCHES MINIMUM AND 0.8440 INCHES MAXIMUM IN
counterbore_diameter0.6700 INCHES MINIMUM AND 0.6900 INCHES MAXIMUM IN
NSN5340-00-914-5394
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: 491691 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: CONTROL ASSY,ENGINE ACFT P/N 544050
•
FIRST STEP DIAMETER: 1.0900 INCHES NOMINAL IN
•
MATERIAL HARDNESS RATING: 38.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM
•
END DIAMETER: 0.3900 INCHES MINIMUM AND 0.4100 INCHES MAXIMUM IN
•
SECOND END DIAMETER: 0.8400 INCHES MINIMUM AND 0.8440 INCHES MAXIMUM IN
•
DISTANCE FROM END TO FIRST STEP: 0.0500 INCHES MINIMUM AND 0.0700 INCHES MAXIMUM IN
•
DESIGN TYPE: SOLID
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT0.2600 INCHES NOMINAL IN
FSC APPLICATION DATACONTROL ASSY,ENGINE ACFT P/N 544050
FIRST STEP DIAMETER1.0900 INCHES NOMINAL IN
MATERIAL HARDNESS RATING38.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM
END DIAMETER0.3900 INCHES MINIMUM AND 0.4100 INCHES MAXIMUM IN
SECOND END DIAMETER0.8400 INCHES MINIMUM AND 0.8440 INCHES MAXIMUM IN
DISTANCE FROM END TO FIRST STEP0.0500 INCHES MINIMUM AND 0.0700 INCHES MAXIMUM IN
DESIGN TYPESOLID
STYLE DESIGNATORSEAT
COUNTERBORE LENGTH0.1200 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 491691?
491691 is a SEAT,HELICAL COMPRESSION SPRING.
What is the NSN for 491691?
491691 is cataloged in the U.S. Government catalog under NSN 5340-00-914-5394. 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.