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NAS1581A4H7 — SCREW,CLOSE TOLERANCE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

NAS1581A4H7: SCREW,CLOSE TOLERANCE.

The SCREW,CLOSE TOLERANCE is a the manufacturer industrial component. Key specifications include head_style: FLAT COUNTERSUNK, grip_length: 0.428 INCHES MINIMUM AND 0.448 INCHES MAXIMUM IN, thread_class: 3A A, grip_diameter: 0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN, head_diameter: 0.350 INCHES MINIMUM AND 0.399 INCHES MAXIMUM IN, thread_length: 0.378 INCHES MINIMUM AND 0.428 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-112-7909, 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
NAS1581A4H7
NSN: 5305-01-112-7909
FSC: 5305 — Screws
CAGE: 80205 — NATIONAL AEROSPACE STANDARDS COMMITTEE AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA INC NOT FOR RFQ OR SOLICITATION USE (USA)
SPECIFICATIONS
materialSTEEL COMP E4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OR STEEL COMP 8735 OR STEEL COMP 6150 OR STEEL COMP 4340 OVERALL
head_styleFLAT COUNTERSUNK
grip_length0.428 INCHES MINIMUM AND 0.448 INCHES MAXIMUM IN
thread_class3A A
grip_diameter0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN
head_diameter0.350 INCHES MINIMUM AND 0.399 INCHES MAXIMUM IN
thread_length0.378 INCHES MINIMUM AND 0.428 INCHES MAXIMUM IN
surface_finish32.0 MICROINCHES THREADS
fastener_length0.826 INCHES MINIMUM AND 0.856 INCHES MAXIMUM IN
hardness_rating36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM OVERALL
thread_directionRIGHT-HAND
countersink_angle99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM
NSN5305-01-112-7909
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: NAS1581A4H7 · 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
•
SURFACE FINISH: 32.0 MICROINCHES THREADS
•
FASTENER LENGTH: 0.826 INCHES MINIMUM AND 0.856 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416,TY 2 CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 0.378 INCHES MINIMUM AND 0.428 INCHES MAXIMUM IN
•
HARDNESS RATING: 36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM OVERALL
•
NOMINAL THREAD DIAMETER: 0.250 INCHES IN
•
HEAD STYLE: FLAT COUNTERSUNK
TECHNICAL CHARACTERISTICS
SURFACE FINISH32.0 MICROINCHES THREADS
SURFACE FINISH32.0 MICROINCHES GRIP
FASTENER LENGTH0.826 INCHES MINIMUM AND 0.856 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TY 2 CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH0.378 INCHES MINIMUM AND 0.428 INCHES MAXIMUM IN
HARDNESS RATING36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM OVERALL
NOMINAL THREAD DIAMETER0.250 INCHES IN
HEAD STYLEFLAT COUNTERSUNK
THREAD DIRECTIONRIGHT-HAND
SPECIFICATION/STANDARD DATA80205-NAS1581 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD
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 1
NAS1581F4H7Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Terminal item — no further procurement; issued until stock is exhaustedNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is NAS1581A4H7?
NAS1581A4H7 is a SCREW,CLOSE TOLERANCE.
What parts can replace NAS1581A4H7?
There is 1 known substitute for NAS1581A4H7: NAS1581F4H7. Substitute compatibility should be verified for your specific system.
What is the NSN for NAS1581A4H7?
NAS1581A4H7 is cataloged in the U.S. Government catalog under NSN 5305-01-112-7909. 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.