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51B581-5-22H — SCREW,CLOSE TOLERANCE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

51B581-5-22H: SCREW,CLOSE TOLERANCE.

The SCREW,CLOSE TOLERANCE is a the manufacturer industrial component. Key specifications include material: STEEL COMP E4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OVERALL, head_style: FLAT COUNTERSUNK, grip_length: 1.365 INCHES MINIMUM AND 1.385 INCHES MAXIMUM IN, thread_class: 3A A, grip_diameter: 0.3110 INCHES MINIMUM AND 0.3120 INCHES MAXIMUM IN, head_diameter: 0.469 INCHES MINIMUM AND 0.474 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-076-6318, 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
51B581-5-22H
NSN: 5305-01-076-6318
FSC: 5305 — Screws
CAGE: 06725 — SPS TECHNOLOGIES, LLC DBA AIR INDUSTRIES COMPANY DIV AIR INDUSTRIES COMPANY (USA)
SPECIFICATIONS
materialSTEEL COMP E4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OVERALL
head_styleFLAT COUNTERSUNK
grip_length1.365 INCHES MINIMUM AND 1.385 INCHES MAXIMUM IN
thread_class3A A
grip_diameter0.3110 INCHES MINIMUM AND 0.3120 INCHES MAXIMUM IN
head_diameter0.469 INCHES MINIMUM AND 0.474 INCHES MAXIMUM IN
thread_length0.349 INCHES MINIMUM AND 0.416 INCHES MAXIMUM IN
surface_finish32.0 MICROINCHES GRIP
fastener_length1.734 INCHES MINIMUM AND 1.781 INCHES MAXIMUM IN
hardness_rating39.0 ROCKWELL C MINIMUM AND 43.0 ROCKWELL C MAXIMUM OVERALL
thread_directionRIGHT-HAND
countersink_angle99.5 DEGREES MINIMUM AND 100.5 DEGREES MAXIMUM
NSN5305-01-076-6318
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 51B581-5-22H · 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 GRIP
•
FASTENER LENGTH: 1.734 INCHES MINIMUM AND 1.781 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416 TY 2 CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 0.349 INCHES MINIMUM AND 0.416 INCHES MAXIMUM IN
•
HARDNESS RATING: 39.0 ROCKWELL C MINIMUM AND 43.0 ROCKWELL C MAXIMUM OVERALL
•
SHANK UNTHREADED HOLE DIAMETER: 0.066 INCHES MINIMUM AND 0.086 INCHES MAXIMUM FIRST HOLE IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-5000 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-5626 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-6049 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
•
NOMINAL THREAD DIAMETER: 0.312 INCHES IN
TECHNICAL CHARACTERISTICS
SURFACE FINISH32.0 MICROINCHES GRIP
FASTENER LENGTH1.734 INCHES MINIMUM AND 1.781 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416 TY 2 CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH0.349 INCHES MINIMUM AND 0.416 INCHES MAXIMUM IN
HARDNESS RATING39.0 ROCKWELL C MINIMUM AND 43.0 ROCKWELL C MAXIMUM OVERALL
SHANK UNTHREADED HOLE DIAMETER0.066 INCHES MINIMUM AND 0.086 INCHES MAXIMUM FIRST HOLE IN
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-5000 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-5626 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-6049 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER0.312 INCHES IN
HEAD STYLEFLAT COUNTERSUNK
THREAD DIRECTIONRIGHT-HAND
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 51B581-5-22H?
51B581-5-22H is a SCREW,CLOSE TOLERANCE.
What is the NSN for 51B581-5-22H?
51B581-5-22H is cataloged in the U.S. Government catalog under NSN 5305-01-076-6318. 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.