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ST21D39-3-7 — STANDOFF,THREADED,SPACING

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

ST21D39-3-7: STANDOFF,THREADED,SPACING.

The STANDOFF,THREADED,SPACING is a the manufacturer industrial component. Key specifications include length: 0.625 INCHES NOMINAL0.625 INCHES NOMINAL IN, material: STEEL CORROSION RESISTING LOCATION NOT OTHERWISE SPECIFIEDSTEEL CORROSION RESISTING LOCATION NOT OTHERWISE SPECIFIED, style_designator: INTERNALLY THREADED FULL LENGTHINTERNALLY THREADED FULL LENGTH, surface_treatment: PASSIVATE OVERALLPASSIVATE OVERALL, width_across_flats: 0.250 INCHES NOMINAL0.250 INCHES NOMINAL IN, cross-sectional_shape: HEXAGONHEXAGON. This part is cataloged in the U.S.

Government catalog under NSN 5340-01-090-1197, 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
ST21D39-3-7
NSN: 5340-01-090-1197
FSC: 5340 — Hardware, Commercial
CAGE: 04236 — LOCKHEED MARTIN CORP (USA)
SPECIFICATIONS
length0.625 INCHES NOMINAL0.625 INCHES NOMINAL IN
materialSTEEL CORROSION RESISTING LOCATION NOT OTHERWISE SPECIFIEDSTEEL CORROSION RESISTING LOCATION NOT OTHERWISE SPECIFIED
style_designatorINTERNALLY THREADED FULL LENGTHINTERNALLY THREADED FULL LENGTH
surface_treatmentPASSIVATE OVERALLPASSIVATE OVERALL
width_across_flats0.250 INCHES NOMINAL0.250 INCHES NOMINAL IN
cross-sectional_shapeHEXAGONHEXAGON
material_document_and_classificationASTM A581 ASSN STD SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIEDASTM A581 ASSN STD SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED
NSN5340-01-090-1197
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: ST21D39-3-7 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
•
WIDTH ACROSS FLATS: 0.250 INCHES NOMINAL0.250 INCHES NOMINAL IN
•
LENGTH: 0.625 INCHES NOMINAL0.625 INCHES NOMINAL IN
•
STYLE DESIGNATOR: INTERNALLY THREADED FULL LENGTHINTERNALLY THREADED FULL LENGTH
•
MATERIAL DOCUMENT AND CLASSIFICATION: ASTM A581 ASSN STD SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIEDASTM A581 ASSN STD SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED
•
CROSS-SECTIONAL SHAPE: HEXAGONHEXAGON
•
SURFACE TREATMENT: PASSIVATE OVERALLPASSIVATE OVERALL
•
MATERIAL: STEEL CORROSION RESISTING LOCATION NOT OTHERWISE SPECIFIEDSTEEL CORROSION RESISTING LOCATION NOT OTHERWISE SPECIFIED
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS0.250 INCHES NOMINAL0.250 INCHES NOMINAL IN
LENGTH0.625 INCHES NOMINAL0.625 INCHES NOMINAL IN
STYLE DESIGNATORINTERNALLY THREADED FULL LENGTHINTERNALLY THREADED FULL LENGTH
MATERIAL DOCUMENT AND CLASSIFICATIONASTM A581 ASSN STD SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIEDASTM A581 ASSN STD SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED
CROSS-SECTIONAL SHAPEHEXAGONHEXAGON
SURFACE TREATMENTPASSIVATE OVERALLPASSIVATE OVERALL
MATERIALSTEEL CORROSION RESISTING LOCATION NOT OTHERWISE SPECIFIEDSTEEL CORROSION RESISTING LOCATION NOT OTHERWISE SPECIFIED
SUBSTITUTES & CROSS-REFERENCES 5
ST21D39-3-10Reference document
Same NSN cross-reference
Reference document — Secondary reference
10391258Reference document
Same NSN cross-reference
Reference document — Informative reference only
8217-SS-1032-7Reference document
Same NSN cross-reference
Reference document — Secondary reference
8217-A-1032-0Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
13032809Reference document
Same NSN cross-reference
Reference document — Secondary reference
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 ST21D39-3-7?
ST21D39-3-7 is a STANDOFF,THREADED,SPACING.
What parts can replace ST21D39-3-7?
There are 5 known substitutes for ST21D39-3-7: ST21D39-3-10, 10391258, 8217-SS-1032-7 and 2 more. Substitute compatibility should be verified for your specific system.
What is the NSN for ST21D39-3-7?
ST21D39-3-7 is cataloged in the U.S. Government catalog under NSN 5340-01-090-1197. 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.