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A631B — BOLT,MACHINE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

A631B: BOLT,MACHINE.

The BOLT,MACHINE is a the manufacturer industrial component. Key specifications include material: STEEL COMP 1035 OVERALL, hole_type: DRILLED, head_style: HEXAGON, head_height: 0.375 INCHES NOMINAL IN, thread_class: 2A A, hole_diameter: 0.062 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 5306-00-431-2588, 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
A631B
NSN: 5306-00-431-2588
FSC: 5306 — Bolts
CAGE: 93343 — WHITE FARM EQUIPMENT CO SUB OF TIC INVESTMENT CORP
SPECIFICATIONS
materialSTEEL COMP 1035 OVERALL
hole_typeDRILLED
head_styleHEXAGON
head_height0.375 INCHES NOMINAL IN
thread_class2A A
hole_diameter0.062 INCHES NOMINAL IN
hole_quantity1
thread_length1.250 INCHES MINIMUM IN
fastener_length1.750 INCHES NOMINAL IN
thread_directionRIGHT-HAND
features_providedUNFINISHED HEAD
width_between_flats0.750 INCHES NOMINAL IN
NSN5306-00-431-2588
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: A631B · 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
•
HEAD HEIGHT: 0.375 INCHES NOMINAL IN
•
FASTENER LENGTH: 1.750 INCHES NOMINAL IN
•
THREAD LENGTH: 1.250 INCHES MINIMUM IN
•
HOLE CONFIGURATION STYLE: HEXAGON FLATS
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-S-634 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
•
NOMINAL THREAD DIAMETER: 0.500 INCHES IN
•
FEATURES PROVIDED: UNFINISHED HEAD
•
HEAD STYLE: HEXAGON
TECHNICAL CHARACTERISTICS
HEAD HEIGHT0.375 INCHES NOMINAL IN
FASTENER LENGTH1.750 INCHES NOMINAL IN
THREAD LENGTH1.250 INCHES MINIMUM IN
HOLE CONFIGURATION STYLEHEXAGON FLATS
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-S-634 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER0.500 INCHES IN
FEATURES PROVIDEDUNFINISHED HEAD
HEAD STYLEHEXAGON
THREAD DIRECTIONRIGHT-HAND
WIDTH BETWEEN FLATS0.750 INCHES NOMINAL IN
SUBSTITUTES & CROSS-REFERENCES 1
472013Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is A631B?
A631B is a BOLT,MACHINE.
What parts can replace A631B?
There is 1 known substitute for A631B: 472013. Substitute compatibility should be verified for your specific system.
What is the NSN for A631B?
A631B is cataloged in the U.S. Government catalog under NSN 5306-00-431-2588. 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.