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21820 FN 12 — RETAINER,HELICAL COMPRESSION SPR

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

21820 FN 12: RETAINER,HELICAL COMPRESSION SPR.

RETAINER,HELICAL COMPRESSION SPR. Key specifications include material: STEEL COMP 416, lip_thickness: 0.070 INCHES NOMINAL IN, overall_height: 1.340 INCHES NOMINAL IN, flange_diameter: 1.650 INCHES NOMINAL IN, flange_thickness: 0.057 INCHES NOMINAL IN, style_designator: PARALLEL. This part is cataloged in the U.S.

Government catalog under NSN 5340-01-112-9874, 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
21820 FN 12
NSN: 5340-01-112-9874
FSC: 5340 — Hardware, Commercial
CAGE: 78062 — SARGENT AEROSPACE & DEFENSE, LLC DBA SARGENT CONTROLS & AEROSPACE DIV SARGENT CONTROLS & AEROSPACE (USA)
SPECIFICATIONS
materialSTEEL COMP 416
lip_thickness0.070 INCHES NOMINAL IN
overall_height1.340 INCHES NOMINAL IN
flange_diameter1.650 INCHES NOMINAL IN
flange_thickness0.057 INCHES NOMINAL IN
style_designatorPARALLEL
end_hole_diameter0.565 INCHES NOMINAL IN
body_inside_diameter1.122 INCHES NOMINAL IN
body_outside_diameter1.300 INCHES NOMINAL IN
casehardening_indicatorNOT CASEHARDENED
material_document_and_classificationAISI 416 ASSN STD SINGLE MATERIAL RESPONSE
NSN5340-01-112-9874
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: 21820 FN 12 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
•
FLANGE DIAMETER: 1.650 INCHES NOMINAL IN
•
FLANGE THICKNESS: 0.057 INCHES NOMINAL IN
•
BODY OUTSIDE DIAMETER: 1.300 INCHES NOMINAL IN
•
STYLE DESIGNATOR: PARALLEL
•
MATERIAL DOCUMENT AND CLASSIFICATION: AISI 416 ASSN STD SINGLE MATERIAL RESPONSE
•
BODY INSIDE DIAMETER: 1.122 INCHES NOMINAL IN
•
CASEHARDENING INDICATOR: NOT CASEHARDENED
TECHNICAL CHARACTERISTICS
FLANGE DIAMETER1.650 INCHES NOMINAL IN
OVERALL HEIGHT1.340 INCHES NOMINAL IN
FLANGE THICKNESS0.057 INCHES NOMINAL IN
BODY OUTSIDE DIAMETER1.300 INCHES NOMINAL IN
STYLE DESIGNATORPARALLEL
MATERIAL DOCUMENT AND CLASSIFICATIONAISI 416 ASSN STD SINGLE MATERIAL RESPONSE
BODY INSIDE DIAMETER1.122 INCHES NOMINAL IN
CASEHARDENING INDICATORNOT CASEHARDENED
LIP THICKNESS0.070 INCHES NOMINAL IN
MATERIALSTEEL COMP 416
SUBSTITUTES & CROSS-REFERENCES 2
20435-001 FIND 23Reference document
Same NSN cross-reference
Reference document — Secondary reference
20435-001Reference document
Same NSN cross-reference
Reference document — Drawing number reference only
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 21820 FN 12?
21820 FN 12 is a RETAINER,HELICAL COMPRESSION SPR.
What parts can replace 21820 FN 12?
There are 2 known substitutes for 21820 FN 12: 20435-001 FIND 23, 20435-001. Substitute compatibility should be verified for your specific system.
What is the NSN for 21820 FN 12?
21820 FN 12 is cataloged in the U.S. Government catalog under NSN 5340-01-112-9874. 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.