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B1821BH125F500L — SCREW,CAP,SOCKET HEAD

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

B1821BH125F500L: SCREW,CAP,SOCKET HEAD.

The SCREW,CAP,SOCKET HEAD is a the manufacturer industrial component. Key specifications include material: PLASTIC POLYAMIDE NYLON LOCKING FEATURE, 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 5305-01-284-9678, 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
B1821BH125F500L
NSN: 5305-01-284-9678
FSC: 5305 — Screws
CAGE: 05047 — THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS (USA)
SPECIFICATIONS
materialPLASTIC POLYAMIDE NYLON LOCKING FEATURE
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 FASTENER
locking_featurePATCH OR STRIP THREADS
thread_directionRIGHT-HAND
surface_treatmentCADMIUM AND CHROMATE FASTENER
width_between_flats1.812 INCHES MINIMUM AND 1.875 INCHES MAXIMUM IN
internal_drive_styleW/O INTERNAL DRIVE
NSN5305-01-284-9678
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: B1821BH125F500L · 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: QQ-P-416 TY 2 CL 3 FED SPEC SINGLE TREATMENT RESPONSE FASTENER
•
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 FASTENER
•
MATERIAL DOCUMENT AND CLASSIFICATION: SAE J429 GR 8 ASSN STD SINGLE MATERIAL RESPONSE FASTENER
•
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 CLASSIFICATIONQQ-P-416 TY 2 CL 3 FED SPEC SINGLE TREATMENT RESPONSE FASTENER
THREAD LENGTH2.750 INCHES MINIMUM AND 2.938 INCHES MAXIMUM IN
HARDNESS RATING32.0 ROCKWELL C MINIMUM AND 38.0 ROCKWELL C MAXIMUM FASTENER
MATERIAL DOCUMENT AND CLASSIFICATIONSAE J429 GR 8 ASSN STD SINGLE MATERIAL RESPONSE FASTENER
NOMINAL THREAD DIAMETER1.250 INCHES IN
HEAD STYLEHEXAGON
THREAD DIRECTIONRIGHT-HAND
WIDTH BETWEEN FLATS1.812 INCHES MINIMUM AND 1.875 INCHES MAXIMUM IN
SUBSTITUTES & CROSS-REFERENCES 5
FF-S-85C TYPE II STYLE 10PReference document
Same NSN cross-reference
Reference document — Identification reference
M18240 1.250-12UNF-2A 5.000LGReference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
MS90727-281LReference document
Same NSN cross-reference
Reference document — Secondary reference
MIL-F-18240,CONF-B HEX HEADReference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
MIL-F-18240,C0N F-B HEX HEADReference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
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 B1821BH125F500L?
B1821BH125F500L is a SCREW,CAP,SOCKET HEAD.
What parts can replace B1821BH125F500L?
There are 5 known substitutes for B1821BH125F500L: FF-S-85C TYPE II STYLE 10P, M18240 1.250-12UNF-2A 5.000LG, MS90727-281L and 2 more. Substitute compatibility should be verified for your specific system.
What is the NSN for B1821BH125F500L?
B1821BH125F500L is cataloged in the U.S. Government catalog under NSN 5305-01-284-9678. 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.