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B1821BH125F500N — SCREW,CAP,HEXAGON HEAD

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

B1821BH125F500N: SCREW,CAP,HEXAGON HEAD.

The SCREW,CAP,HEXAGON HEAD is a the manufacturer industrial component. Key specifications include material: STEEL OVERALL, head_style: HEXAGON, head_height: 0.749 INCHES MINIMUM AND 0.813 INCHES MAXIMUM IN, thread_class: 2A A, thread_length: 2.750 INCHES MINIMUM AND 2.938 INCHES MAXIMUM IN, fastener_length: 4.812 INCHES MINIMUM AND 5.000 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-00-066-8173, 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
B1821BH125F500N
NSN: 5305-00-066-8173
FSC: 5305 — Screws
CAGE: 80204 — AMERICAN NATIONAL STANDARDS INSTITUTE INCORPORATED DBA AMERICAN NATIONAL STANDARDS INSTITUTE (USA)
SPECIFICATIONS
materialSTEEL OVERALL
head_styleHEXAGON
head_height0.749 INCHES MINIMUM AND 0.813 INCHES MAXIMUM IN
thread_class2A A
thread_length2.750 INCHES MINIMUM AND 2.938 INCHES MAXIMUM IN
fastener_length4.812 INCHES MINIMUM AND 5.000 INCHES MAXIMUM IN
hardness_rating32.0 ROCKWELL C MINIMUM AND 38.0 ROCKWELL C MAXIMUM OVERALL
thread_directionRIGHT-HAND
surface_treatmentZINC AND CHROMATE OVERALL
width_between_flats1.812 INCHES MINIMUM AND 1.875 INCHES MAXIMUM IN
nominal_thread_diameter1.250 INCHES IN
minimum_tensile_strength150000 POUNDS PER SQUARE INCH LBS
NSN5305-00-066-8173
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: B1821BH125F500N · OEM ⚠ VERIFY BEFORE ORDERING Verify thread pitch before ordering — metric (M8×1.25) ≠ imperial (5/16-18). Wrong thread = wrong part. Grade/class stamped on bolt head determines tensile strength ✓ BROKER TIP Grade/class stamped on head determines tensile strength. Grade 8 > Grade 5 > Grade 2. Always confirm head marking matches specification requirement PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
HEAD HEIGHT: 0.749 INCHES MINIMUM AND 0.813 INCHES MAXIMUM IN
•
FASTENER LENGTH: 4.812 INCHES MINIMUM AND 5.000 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: ASTM B633 TY 2 SC 3 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 2.750 INCHES MINIMUM AND 2.938 INCHES MAXIMUM IN
•
HARDNESS RATING: 32.0 ROCKWELL C MINIMUM AND 38.0 ROCKWELL C MAXIMUM OVERALL
•
MATERIAL DOCUMENT AND CLASSIFICATION: SAE J429 GR8 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
NOMINAL THREAD DIAMETER: 1.250 INCHES IN
•
HEAD STYLE: HEXAGON
TECHNICAL CHARACTERISTICS
HEAD HEIGHT0.749 INCHES MINIMUM AND 0.813 INCHES MAXIMUM IN
FASTENER LENGTH4.812 INCHES MINIMUM AND 5.000 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONASTM B633 TY 2 SC 3 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH2.750 INCHES MINIMUM AND 2.938 INCHES MAXIMUM IN
HARDNESS RATING32.0 ROCKWELL C MINIMUM AND 38.0 ROCKWELL C MAXIMUM OVERALL
MATERIAL DOCUMENT AND CLASSIFICATIONSAE J429 GR8 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER1.250 INCHES IN
HEAD STYLEHEXAGON
THREAD DIRECTIONRIGHT-HAND
WIDTH BETWEEN FLATS1.812 INCHES MINIMUM AND 1.875 INCHES MAXIMUM IN
OTHER ITEMS IN FSC 5305 — Screws
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5305-00-001-5016 5305-00-001-9160 5305-00-001-9629 5305-00-001-9742 5305-00-001-9768 5305-00-003-4306 5305-00-003-6694 5305-00-003-6753
SUBSTITUTES & CROSS-REFERENCES 4
FF-S-85Reference document
Same NSN cross-reference
Reference document — Secondary reference
5305000668173Reference document
Same NSN cross-reference
Reference document — Informative reference only
MS90727-281Reference document
Same NSN cross-reference
Reference document — Secondary reference
B18.24Reference document
Same NSN cross-reference
Reference document — Secondary reference
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 B1821BH125F500N?
B1821BH125F500N is a SCREW,CAP,HEXAGON HEAD.
What parts can replace B1821BH125F500N?
There are 4 known substitutes for B1821BH125F500N: FF-S-85, 5305000668173, MS90727-281 and 1 more. Substitute compatibility should be verified for your specific system.
What is the NSN for B1821BH125F500N?
B1821BH125F500N is cataloged in the U.S. Government catalog under NSN 5305-00-066-8173. 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.