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51B221-11 — SCREW,MACHINE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

51B221-11: SCREW,MACHINE.

The SCREW,MACHINE is a the manufacturer industrial component. Key specifications include head_style: BUTTON, head_height: 0.109 INCHES NOMINAL IN, thread_class: 3A A, head_diameter: 0.390 INCHES NOMINAL IN, thread_length: 0.276 INCHES MINIMUM IN, screw_material: STEEL. This part is cataloged in the U.S.

Government catalog under NSN 5305-00-809-1665, 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
51B221-11
NSN: 5305-00-809-1665
FSC: 5305 — Screws
CAGE: 79U29 — NORTHROP GRUMMAN SYSTEMS CORPORATION (USA)
SPECIFICATIONS
head_styleBUTTON
head_height0.109 INCHES NOMINAL IN
thread_class3A A
head_diameter0.390 INCHES NOMINAL IN
thread_length0.276 INCHES MINIMUM IN
screw_materialSTEEL
fastener_length0.963 INCHES NOMINAL IN
thread_directionRIGHT-HAND
internal_drive_styleTORQUE SET
nominal_thread_diameter0.190 INCHES IN
screw_surface_treatmentCADMIUM
minimum_tensile_strength180000 POUNDS PER SQUARE INCH LBS
NSN5305-00-809-1665
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 51B221-11 · 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
•
HEAD HEIGHT: 0.109 INCHES NOMINAL IN
•
SCREW SURFACE TREATMENT: CADMIUM
•
FASTENER LENGTH: 0.963 INCHES NOMINAL IN
•
THREAD LENGTH: 0.276 INCHES MINIMUM IN
•
NOMINAL THREAD DIAMETER: 0.190 INCHES IN
•
HEAD STYLE: BUTTON
•
THREAD DIRECTION: RIGHT-HAND
•
SCREW MATERIAL: STEEL
TECHNICAL CHARACTERISTICS
HEAD HEIGHT0.109 INCHES NOMINAL IN
SCREW SURFACE TREATMENTCADMIUM
FASTENER LENGTH0.963 INCHES NOMINAL IN
THREAD LENGTH0.276 INCHES MINIMUM IN
NOMINAL THREAD DIAMETER0.190 INCHES IN
HEAD STYLEBUTTON
THREAD DIRECTIONRIGHT-HAND
SCREW MATERIALSTEEL
MINIMUM TENSILE STRENGTH180000 POUNDS PER SQUARE INCH LBS
INTERNAL DRIVE STYLETORQUE SET
OTHER ITEMS IN FSC 5305 — Screws
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5305-00-000-0094 5305-00-000-1397 5305-00-000-2625 5305-00-000-3669 5305-00-000-3830 5305-00-000-3831
SUBSTITUTES & CROSS-REFERENCES

No substitute or cross-reference records for this part.

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 51B221-11?
51B221-11 is a SCREW,MACHINE.
What is the NSN for 51B221-11?
51B221-11 is cataloged in the U.S. Government catalog under NSN 5305-00-809-1665. 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.