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A51K56639-11 — SCREW,CAP,SOCKET HEAD

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

A51K56639-11: SCREW,CAP,SOCKET HEAD.

The SCREW,CAP,SOCKET HEAD is a the manufacturer industrial component. Key specifications include material: STEEL COMP 302 OR STEEL COMP 303 OR STEEL COMP 304 OR STEEL COMP 305 OR STEEL COMP 316 OVERALL, head_style: FLAT CHAMFER, head_height: 0.159 INCHES MINIMUM AND 0.164 INCHES MAXIMUM IN, thread_class: 3A A, head_diameter: 0.262 INCHES MINIMUM AND 0.270 INCHES MAXIMUM IN, thread_length: 1.000 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-00-005-0050, 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
A51K56639-11
NSN: 5305-00-005-0050
FSC: 5305 — Screws
CAGE: 79RG9 — NORTHROP GRUMMAN SYSTEMS CORPORATION (USA)
SPECIFICATIONS
materialSTEEL COMP 302 OR STEEL COMP 303 OR STEEL COMP 304 OR STEEL COMP 305 OR STEEL COMP 316 OVERALL
head_styleFLAT CHAMFER
head_height0.159 INCHES MINIMUM AND 0.164 INCHES MAXIMUM IN
thread_class3A A
head_diameter0.262 INCHES MINIMUM AND 0.270 INCHES MAXIMUM IN
thread_length1.000 INCHES MAXIMUM IN
fastener_length0.984 INCHES MINIMUM AND 1.016 INCHES MAXIMUM IN
hardness_rating80.0 ROCKWELL B MINIMUM OVERALL
thread_directionRIGHT-HAND
surface_treatmentPASSIVATE OVERALL
width_across_flats0.140 INCHES MINIMUM AND 0.142 INCHES MAXIMUM IN
internal_drive_styleHEXAGON
NSN5305-00-005-0050
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: A51K56639-11 · 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: 0.140 INCHES MINIMUM AND 0.142 INCHES MAXIMUM IN
•
HEAD HEIGHT: 0.159 INCHES MINIMUM AND 0.164 INCHES MAXIMUM IN
•
FASTENER LENGTH: 0.984 INCHES MINIMUM AND 1.016 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 1.000 INCHES MAXIMUM IN
•
HARDNESS RATING: 80.0 ROCKWELL B MINIMUM OVERALL
•
SHANK UNTHREADED HOLE DIAMETER: 0.038 INCHES MINIMUM AND 0.043 INCHES MAXIMUM FIRST HOLE IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: 66 FED STD ALL MATERIAL RESPONSES OVERALL
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS0.140 INCHES MINIMUM AND 0.142 INCHES MAXIMUM IN
HEAD HEIGHT0.159 INCHES MINIMUM AND 0.164 INCHES MAXIMUM IN
FASTENER LENGTH0.984 INCHES MINIMUM AND 1.016 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH1.000 INCHES MAXIMUM IN
HARDNESS RATING80.0 ROCKWELL B MINIMUM OVERALL
SHANK UNTHREADED HOLE DIAMETER0.038 INCHES MINIMUM AND 0.043 INCHES MAXIMUM FIRST HOLE IN
MATERIAL DOCUMENT AND CLASSIFICATION66 FED STD ALL MATERIAL RESPONSES OVERALL
NOMINAL THREAD DIAMETER0.164 INCHES IN
HEAD STYLEFLAT CHAMFER
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
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is A51K56639-11?
A51K56639-11 is a SCREW,CAP,SOCKET HEAD.
What is the NSN for A51K56639-11?
A51K56639-11 is cataloged in the U.S. Government catalog under NSN 5305-00-005-0050. 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.