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Technical Data Sheet
PartsTable / COMPONENT / 21FC720
21FC720 ✓ Verified by PartsTable
— · NUT WASHER
WHAT YOU NEED TO KNOW
Match nut grade to bolt grade for full strength Lock nuts prevent loosening under vibration
Don't mix grades — weakens the joint
PRODUCT OVERVIEW

The NUT,SELF-LOCKING,HEXAGON is a the manufacturer industrial component. Key specifications include material: STEEL COMP 1117 OVERALL, nut_style: HEXAGON, nut_height: 0.463 INCHES NOMINAL IN, temp_rating: 550.0 FAHRENHEIT NOMINAL DEGF, thread_class: 3B, thread_series: UNF. This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5310-00-527-3819, 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
21FC720
NSN: 5310-00-527-3819
FSC: 5310
CAGE: 56878 — SPS TECHNOLOGIES, LLC DBA PB FASTENERS (USA)
SPECIFICATIONS
materialSTEEL COMP 1117 OVERALL
nut_styleHEXAGON
nut_height0.463 INCHES NOMINAL IN
temp_rating550.0 FAHRENHEIT NOMINAL DEGF
thread_class3B
thread_seriesUNF
locking_featurePREVAILING TORQUE ALL METAL DESIGN
thread_directionRIGHT-HAND
surface_treatmentCADMIUM OVERALL
width_across_flats0.625 INCHES NOMINAL IN
nominal_thread_size0.438 INCHES IN
bearing_surface_typeCHAMFERED
NSN5310-00-527-3819
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 21FC720 · 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
•
NUT HEIGHT: 0.463 INCHES NOMINAL IN
•
THREAD CLASS: 3B
•
THREAD DIRECTION: RIGHT-HAND
•
BEARING SURFACE TYPE: CHAMFERED
•
NOMINAL THREAD SIZE: 0.438 INCHES IN
•
NUT STYLE: HEXAGON
•
TEMP RATING: 550.0 FAHRENHEIT NOMINAL DEGF
•
THREAD SERIES: UNF
TECHNICAL CHARACTERISTICS (FLIS)
NUT HEIGHT0.463 INCHES NOMINAL IN
THREAD CLASS3B
THREAD DIRECTIONRIGHT-HAND
BEARING SURFACE TYPECHAMFERED
NOMINAL THREAD SIZE0.438 INCHES IN
NUT STYLEHEXAGON
TEMP RATING550.0 FAHRENHEIT NOMINAL DEGF
THREAD SERIESUNF
MATERIALSTEEL COMP 1117 OVERALL
SURFACE TREATMENTCADMIUM OVERALL
VERIFIED SUBSTITUTES & CROSS-REFERENCES 9
7736797P1Interchangeable
interchangeable cross-reference
interchangeable
80-030Interchangeable
interchangeable cross-reference
interchangeable
3196SInterchangeable
interchangeable cross-reference
interchangeable
F3U223HInterchangeable
interchangeable cross-reference
interchangeable
WD-1Interchangeable
interchangeable cross-reference
interchangeable
800-0030Interchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusCANCELLED
Availability—
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is 21FC720?
21FC720 is a NUT,SELF-LOCKING,HEXAGON.
What parts can replace 21FC720?
There are 9 known substitutes for 21FC720: 7736797P1, 80-030, 3196S and 6 more. Substitute compatibility should be verified for your specific system.
Is 21FC720 still available?
21FC720 is currently cancelled.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026