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21AX638 — NUT,SELF-LOCKING,HEXAGON

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

21AX638: NUT,SELF-LOCKING,HEXAGON.

The NUT,SELF-LOCKING,HEXAGON is a the manufacturer industrial component. Key specifications include material: STEEL OVERALL, nut_height: 0.909 INCHES NOMINAL IN, thread_class: 3B, thread_series: UNF, special_features: MATERIAL:STEEL WITH NYLON INSERT, thread_direction: RIGHT-HAND. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-552-7972, 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
21AX638
NSN: 5310-01-552-7972
FSC: 5310 — Nuts and Washers
CAGE: 89619 — MACK TRUCKS, INC. DBA MACUNGIE OPERATIONS DIV LEHIGH VALLEY OPERATIONS (USA)
SPECIFICATIONS
materialSTEEL OVERALL
nut_height0.909 INCHES NOMINAL IN
thread_class3B
thread_seriesUNF
special_featuresMATERIAL:STEEL WITH NYLON INSERT
thread_directionRIGHT-HAND
width_across_flats1.014 INCHES NOMINAL IN
nominal_thread_size0.500 INCHES IN
thread_quantity_per_inch20
part_name_assigned_by_controlling_agencyNUT, HEX LOCK
NSN5310-01-552-7972
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 21AX638 · 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: 1.014 INCHES NOMINAL IN
•
THREAD SERIES: UNF
•
THREAD DIRECTION: RIGHT-HAND
•
NOMINAL THREAD SIZE: 0.500 INCHES IN
•
NUT HEIGHT: 0.909 INCHES NOMINAL IN
•
THREAD CLASS: 3B
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS1.014 INCHES NOMINAL IN
THREAD SERIESUNF
THREAD DIRECTIONRIGHT-HAND
NOMINAL THREAD SIZE0.500 INCHES IN
NUT HEIGHT0.909 INCHES NOMINAL IN
SPECIAL FEATURESMATERIAL:STEEL WITH NYLON INSERT
PART NAME ASSIGNED BY CONTROLLING AGENCYNUT, HEX LOCK
THREAD CLASS3B
THREAD QUANTITY PER INCH20
MATERIALSTEEL OVERALL
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
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 21AX638?
21AX638 is a NUT,SELF-LOCKING,HEXAGON.
What is the NSN for 21AX638?
21AX638 is cataloged in the U.S. Government catalog under NSN 5310-01-552-7972. 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.