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645398S820 — NUT,PLAIN,CASTELLATED,HEXAGON

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

645398S820: NUT,PLAIN,CASTELLATED,HEXAGON.

The NUT,PLAIN,CASTELLATED,HEXAGON is a the manufacturer industrial component. Key specifications include material: ALUMINUM ALLOY OVERALL, nut_style: CASTELLATED, HEXAGON, nut_height: 0.321 INCHES NOMINAL IN, thread_class: 2B, thread_series: UNF, thread_direction: RIGHT-HAND. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-021-8935, 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
645398S820
NSN: 5310-01-021-8935
FSC: 5310 — Nuts and Washers
CAGE: 3H889 — PARKER-HANNIFIN CORPORATION DBA PNEUTRONICS (USA)
SPECIFICATIONS
materialALUMINUM ALLOY OVERALL
nut_styleCASTELLATED, HEXAGON
nut_height0.321 INCHES NOMINAL IN
thread_class2B
thread_seriesUNF
thread_directionRIGHT-HAND
width_across_flats0.748 INCHES NOMINAL IN
nominal_thread_size0.500 INCHES IN
bearing_surface_typeCHAMFERED
thread_quantity_per_inch20
NSN5310-01-021-8935
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 645398S820 · OEM ⚠ VERIFY BEFORE ORDERING Grade matters for torque spec — don't mix grades. A Grade 5 nut on a Grade 8 bolt weakens the joint. Lock nuts, wing nuts, and castle nuts are NOT interchangeable with standard hex ✓ BROKER TIP Match nut to bolt thread class and material. Stainless bolt + zinc nut = galvanic corrosion. Always verify finish matches (plain, zinc, hot-dip galvanized) PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
WIDTH ACROSS FLATS: 0.748 INCHES NOMINAL IN
•
THREAD SERIES: UNF
•
THREAD DIRECTION: RIGHT-HAND
•
NOMINAL THREAD SIZE: 0.500 INCHES IN
•
NUT HEIGHT: 0.321 INCHES NOMINAL IN
•
NUT STYLE: CASTELLATED, HEXAGON
•
THREAD CLASS: 2B
•
THREAD QUANTITY PER INCH: 20
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS0.748 INCHES NOMINAL IN
THREAD SERIESUNF
THREAD DIRECTIONRIGHT-HAND
NOMINAL THREAD SIZE0.500 INCHES IN
NUT HEIGHT0.321 INCHES NOMINAL IN
NUT STYLECASTELLATED, HEXAGON
THREAD CLASS2B
THREAD QUANTITY PER INCH20
MATERIALALUMINUM ALLOY OVERALL
BEARING SURFACE TYPECHAMFERED
OTHER ITEMS IN FSC 5310 — Nuts and Washers
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5310-00-000-0040 5310-00-000-0077 5310-00-000-0079 5310-00-000-1146 5310-00-000-3815 5310-00-000-4532 5310-00-000-4540
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 645398S820?
645398S820 is a NUT,PLAIN,CASTELLATED,HEXAGON.
What is the NSN for 645398S820?
645398S820 is cataloged in the U.S. Government catalog under NSN 5310-01-021-8935. 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.