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121557-4-A9PX — SCREW,CLOSE TOLERANCE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

121557-4-A9PX: SCREW,CLOSE TOLERANCE.

The SCREW,CLOSE TOLERANCE is a the manufacturer industrial component. Key specifications include material: STEEL COMP H11 OVERALL, grip_length: 0.552 INCHES MINIMUM AND 0.572 INCHES MAXIMUM IN, thread_class: 3A A, grip_diameter: 0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN, thread_length: 0.345 INCHES MINIMUM AND 0.395 INCHES MAXIMUM IN, fastener_length: 0.917 INCHES MINIMUM AND 0.947 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-406-8668, 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
121557-4-A9PX
NSN: 5305-01-406-8668
FSC: 5305 — Screws
CAGE: 80539 — SPS TECHNOLOGIES, LLC DBA AEROSPACE FASTENERS GROUP DIV AEROSPACE - SANTA ANA (USA)
SPECIFICATIONS
materialSTEEL COMP H11 OVERALL
grip_length0.552 INCHES MINIMUM AND 0.572 INCHES MAXIMUM IN
thread_class3A A
grip_diameter0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN
thread_length0.345 INCHES MINIMUM AND 0.395 INCHES MAXIMUM IN
fastener_length0.917 INCHES MINIMUM AND 0.947 INCHES MAXIMUM IN
hardness_rating46.0 ROCKWELL C MINIMUM AND 49.0 ROCKWELL C MAXIMUM OVERALL
thread_directionRIGHT-HAND
countersink_angle99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM
surface_treatmentCADMIUM OVERALL
internal_drive_styleOFFSET CRUCIFORM (TORQUE SET)
nominal_thread_diameter0.250 INCHES IN
NSN5305-01-406-8668
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 121557-4-A9PX · 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
•
FASTENER LENGTH: 0.917 INCHES MINIMUM AND 0.947 INCHES MAXIMUM IN
•
THREAD LENGTH: 0.345 INCHES MINIMUM AND 0.395 INCHES MAXIMUM IN
•
HARDNESS RATING: 46.0 ROCKWELL C MINIMUM AND 49.0 ROCKWELL C MAXIMUM OVERALL
•
NOMINAL THREAD DIAMETER: 0.250 INCHES IN
•
THREAD DIRECTION: RIGHT-HAND
•
SPECIFICATION/STANDARD DATA: 81755-C7984-4-10R PROFESSIONAL/INDUSTRIAL ASSOCIATION SPECIFICATION
•
GRIP LENGTH: 0.552 INCHES MINIMUM AND 0.572 INCHES MAXIMUM IN
•
GRIP DIAMETER: 0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
FASTENER LENGTH0.917 INCHES MINIMUM AND 0.947 INCHES MAXIMUM IN
THREAD LENGTH0.345 INCHES MINIMUM AND 0.395 INCHES MAXIMUM IN
HARDNESS RATING46.0 ROCKWELL C MINIMUM AND 49.0 ROCKWELL C MAXIMUM OVERALL
NOMINAL THREAD DIAMETER0.250 INCHES IN
THREAD DIRECTIONRIGHT-HAND
SPECIFICATION/STANDARD DATA81755-C7984-4-10R PROFESSIONAL/INDUSTRIAL ASSOCIATION SPECIFICATION
GRIP LENGTH0.552 INCHES MINIMUM AND 0.572 INCHES MAXIMUM IN
GRIP DIAMETER0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN
SURFACE TREATMENTCADMIUM OVERALL
INTERNAL DRIVE STYLEOFFSET CRUCIFORM (TORQUE 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 2
VT1693F4-9XSame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
C7984-4-9RReference 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 121557-4-A9PX?
121557-4-A9PX is a SCREW,CLOSE TOLERANCE.
What parts can replace 121557-4-A9PX?
There are 2 known substitutes for 121557-4-A9PX: VT1693F4-9X, C7984-4-9R. Substitute compatibility should be verified for your specific system.
What is the NSN for 121557-4-A9PX?
121557-4-A9PX is cataloged in the U.S. Government catalog under NSN 5305-01-406-8668. 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.