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NAS1581C4H5 — SCREW,CLOSE TOLERANCE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

NAS1581C4H5: SCREW,CLOSE TOLERANCE.

The SCREW,CLOSE TOLERANCE is a the manufacturer industrial component. Key specifications include material: IRON ALLOY 660 OVERALL, head_style: FLAT COUNTERSUNK, grip_length: 0.302 INCHES MINIMUM AND 0.322 INCHES MAXIMUM IN, thread_class: 3A A, grip_diameter: 0.2490 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN, head_diameter: 0.350 INCHES MINIMUM AND 0.399 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-00-595-5986, 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
NAS1581C4H5
NSN: 5305-00-595-5986
FSC: 5305 — Screws
CAGE: 80205 — NATIONAL AEROSPACE STANDARDS COMMITTEE AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA INC NOT FOR RFQ OR SOLICITATION USE (USA)
SPECIFICATIONS
materialIRON ALLOY 660 OVERALL
head_styleFLAT COUNTERSUNK
grip_length0.302 INCHES MINIMUM AND 0.322 INCHES MAXIMUM IN
thread_class3A A
grip_diameter0.2490 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_length0.700 INCHES MINIMUM AND 0.730 INCHES MAXIMUM IN
thread_directionRIGHT-HAND
countersink_angle99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM
surface_treatmentPASSIVATE OVERALL
NSN5305-00-595-5986
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: NAS1581C4H5 · 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: 0.700 INCHES MINIMUM AND 0.730 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 0.378 INCHES MINIMUM AND 0.428 INCHES MAXIMUM IN
•
SHANK UNTHREADED HOLE DIAMETER: 0.076 INCHES MINIMUM AND 0.086 INCHES MAXIMUM FIRST HOLE IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS5731 ASSN STD 1ST MATERIAL RESPONSE OR AMS5735 ASSN STD 2ND MATERIAL RESPONSE OR AMS5737 ASSN STD 3RD MATERIAL RESPONSE OVERALL
TECHNICAL CHARACTERISTICS
SURFACE FINISH32.0 MICROINCHES THREADS
SURFACE FINISH32.0 MICROINCHES GRIP
SURFACE FINISH32.0 MICROINCHES BEARING SURFACE OF HEAD
FASTENER LENGTH0.700 INCHES MINIMUM AND 0.730 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH0.378 INCHES MINIMUM AND 0.428 INCHES MAXIMUM IN
SHANK UNTHREADED HOLE DIAMETER0.076 INCHES MINIMUM AND 0.086 INCHES MAXIMUM FIRST HOLE IN
MATERIAL DOCUMENT AND CLASSIFICATIONAMS5731 ASSN STD 1ST MATERIAL RESPONSE OR AMS5735 ASSN STD 2ND MATERIAL RESPONSE OR AMS5737 ASSN STD 3RD MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER0.250 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
GB510BF4-5Reference document
Same NSN cross-reference
Reference document — Secondary reference
GB510DC4C5DSame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
76121-4-5Reference 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 NAS1581C4H5?
NAS1581C4H5 is a SCREW,CLOSE TOLERANCE.
What parts can replace NAS1581C4H5?
There are 3 known substitutes for NAS1581C4H5: GB510BF4-5, GB510DC4C5D, 76121-4-5. Substitute compatibility should be verified for your specific system.
What is the NSN for NAS1581C4H5?
NAS1581C4H5 is cataloged in the U.S. Government catalog under NSN 5305-00-595-5986. 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.