PartsTable
Technical Data Sheet
Download PDF

121557-3-A11FX — SCREW,SHOULDER

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

121557-3-A11FX: SCREW,SHOULDER.

The SCREW,SHOULDER is a the manufacturer industrial component. Key specifications include material: STEEL COMP H11 OVERALL, head_style: FLAT COUNTERSUNK, thread_class: 3A A, head_diameter: 0.325 INCHES MINIMUM AND 0.385 INCHES MAXIMUM IN, thread_length: 0.261 INCHES MINIMUM AND 0.323 INCHES MAXIMUM IN, shoulder_shape: ROUND FIRST SHOULDER. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-428-2140, 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
121557-3-A11FX
NSN: 5305-01-428-2140
FSC: 5305 — Screws
CAGE: 56878 — SPS TECHNOLOGIES, LLC DBA PB FASTENERS (USA)
SPECIFICATIONS
materialSTEEL COMP H11 OVERALL
head_styleFLAT COUNTERSUNK
thread_class3A A
head_diameter0.325 INCHES MINIMUM AND 0.385 INCHES MAXIMUM IN
thread_length0.261 INCHES MINIMUM AND 0.323 INCHES MAXIMUM IN
shoulder_shapeROUND FIRST SHOULDER
fastener_length0.996 INCHES MINIMUM AND 1.026 INCHES MAXIMUM IN
hardness_rating46.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM OVERALL
shoulder_length0.313 INCHES MINIMUM AND 0.333 INCHES MAXIMUM FIRST SHOULDER IN
thread_directionRIGHT-HAND
countersink_angle99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM
shoulder_diameter0.2041 INCHES MINIMUM AND 0.2051 INCHES MAXIMUM FIRST SHOULDER IN
NSN5305-01-428-2140
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 121557-3-A11FX · 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: 0.996 INCHES MINIMUM AND 1.026 INCHES MAXIMUM IN
•
SHOULDER LENGTH: 0.313 INCHES MINIMUM AND 0.333 INCHES MAXIMUM FIRST SHOULDER IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: NAS 672 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
•
SHOULDER DIAMETER: 0.2041 INCHES MINIMUM AND 0.2051 INCHES MAXIMUM FIRST SHOULDER IN
•
THREAD LENGTH: 0.261 INCHES MINIMUM AND 0.323 INCHES MAXIMUM IN
•
SHOULDER SHAPE: ROUND FIRST SHOULDER
•
HARDNESS RATING: 46.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM OVERALL
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 6487 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
TECHNICAL CHARACTERISTICS
FASTENER LENGTH0.996 INCHES MINIMUM AND 1.026 INCHES MAXIMUM IN
SHOULDER LENGTH0.313 INCHES MINIMUM AND 0.333 INCHES MAXIMUM FIRST SHOULDER IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONNAS 672 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
SHOULDER DIAMETER0.2041 INCHES MINIMUM AND 0.2051 INCHES MAXIMUM FIRST SHOULDER IN
THREAD LENGTH0.261 INCHES MINIMUM AND 0.323 INCHES MAXIMUM IN
SHOULDER SHAPEROUND FIRST SHOULDER
HARDNESS RATING46.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM OVERALL
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 6487 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER0.190 INCHES IN
HEAD STYLEFLAT COUNTERSUNK
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 3
HO44-3-11RReference document
Same NSN cross-reference
Reference document — Secondary reference
C7984-3-11RSame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
AIC984-3-11RReference 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
Ready to buy 121557-3-A11FX?
Compare prices from verified sellers on eBay
Buy on eBay →
As an eBay Partner, PartsTable may earn a commission. Your price is not affected.
FREQUENTLY ASKED QUESTIONS
What is 121557-3-A11FX?
121557-3-A11FX is a SCREW,SHOULDER.
What parts can replace 121557-3-A11FX?
There are 3 known substitutes for 121557-3-A11FX: HO44-3-11R, C7984-3-11R, AIC984-3-11R. Substitute compatibility should be verified for your specific system.
What is the NSN for 121557-3-A11FX?
121557-3-A11FX is cataloged in the U.S. Government catalog under NSN 5305-01-428-2140. This indicates validated use in U.S. government and defense supply chains.
Community Feedback
Leave a Comment
Comments are reviewed before appearing. You will receive an email to verify before your comment appears.

Request a Quote — 121557-3-A11FX

✓ 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.