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91251A378 — SCREW,CAP,SOCKET HEAD

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

91251A378: SCREW,CAP,SOCKET HEAD.

The SCREW,CAP,SOCKET HEAD is a the manufacturer industrial component. Key specifications include material: STEEL COMP 631 OVERALL, head_style: FLAT FILLISTER, head_height: 0.312 INCHES NOMINAL IN, thread_class: 3A A, head_diameter: 0.469 INCHES NOMINAL IN, thread_length: 0.500 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-644-5162, 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
91251A378
NSN: 5305-01-644-5162
FSC: 5305 — Screws
CAGE: 39428 — MCMASTER-CARR SUPPLY CO (USA)
SPECIFICATIONS
materialSTEEL COMP 631 OVERALL
head_styleFLAT FILLISTER
head_height0.312 INCHES NOMINAL IN
thread_class3A A
head_diameter0.469 INCHES NOMINAL IN
thread_length0.500 INCHES NOMINAL IN
fastener_length0.500 INCHES NOMINAL IN
hardness_rating37.0 ROCKWELL C NOMINAL OVERALL
thread_directionRIGHT-HAND
surface_treatmentOXIDE OVERALL
width_across_flats0.250 INCHES NOMINAL IN
internal_drive_styleHEXAGON
NSN5305-01-644-5162
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 91251A378 · 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
•
WIDTH ACROSS FLATS: 0.250 INCHES NOMINAL IN
•
HEAD HEIGHT: 0.312 INCHES NOMINAL IN
•
FASTENER LENGTH: 0.500 INCHES NOMINAL IN
•
THREAD LENGTH: 0.500 INCHES NOMINAL IN
•
HARDNESS RATING: 37.0 ROCKWELL C NOMINAL OVERALL
•
NOMINAL THREAD DIAMETER: 0.3125 INCHES IN
•
HEAD STYLE: FLAT FILLISTER
•
THREAD DIRECTION: RIGHT-HAND
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS0.250 INCHES NOMINAL IN
HEAD HEIGHT0.312 INCHES NOMINAL IN
FASTENER LENGTH0.500 INCHES NOMINAL IN
THREAD LENGTH0.500 INCHES NOMINAL IN
HARDNESS RATING37.0 ROCKWELL C NOMINAL OVERALL
NOMINAL THREAD DIAMETER0.3125 INCHES IN
HEAD STYLEFLAT FILLISTER
THREAD DIRECTIONRIGHT-HAND
COLORBLACK OVERALL
SURFACE TREATMENTOXIDE OVERALL
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

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 91251A378?
91251A378 is a SCREW,CAP,SOCKET HEAD.
What is the NSN for 91251A378?
91251A378 is cataloged in the U.S. Government catalog under NSN 5305-01-644-5162. 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.