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8756521 — BOLT,MACHINE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

8756521: BOLT,MACHINE.

The BOLT,MACHINE is a the manufacturer industrial component. Key specifications include material: STEEL COMP 1340 OR STEEL COMP 4140 OR STEEL COMP 5140 OR STEEL COMP 8640 OVERALL, head_style: HEXAGON, head_height: 0.297 INCHES NOMINAL IN, thread_class: 2A A, thread_length: 0.688 INCHES MINIMUM AND 0.812 INCHES MAXIMUM IN, fastener_length: 6.250 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 5306-00-679-9855, 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
8756521
NSN: 5306-00-679-9855
FSC: 5306 — Bolts
CAGE: 19207 — U S ARMY TANK AUTOMOTIVE COMMAND AMSTA-IM-MM (USA)
SPECIFICATIONS
materialSTEEL COMP 1340 OR STEEL COMP 4140 OR STEEL COMP 5140 OR STEEL COMP 8640 OVERALL
head_styleHEXAGON
head_height0.297 INCHES NOMINAL IN
thread_class2A A
thread_length0.688 INCHES MINIMUM AND 0.812 INCHES MAXIMUM IN
fastener_length6.250 INCHES NOMINAL IN
hardness_rating30.0 ROCKWELL C MINIMUM AND 34.0 ROCKWELL C MAXIMUM OVERALL
thread_directionRIGHT-HAND
features_providedFINISHED HEAD
width_between_flats0.736 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN
nominal_thread_diameter0.500 INCHES IN
thread_quantity_per_inch20
NSN5306-00-679-9855
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 8756521 · 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: 0.297 INCHES NOMINAL IN
•
FASTENER LENGTH: 6.250 INCHES NOMINAL IN
•
THREAD LENGTH: 0.688 INCHES MINIMUM AND 0.812 INCHES MAXIMUM IN
•
HARDNESS RATING: 30.0 ROCKWELL C MINIMUM AND 34.0 ROCKWELL C MAXIMUM OVERALL
•
SHANK UNTHREADED HOLE DIAMETER: 0.109 INCHES NOMINAL FIRST HOLE IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: ASTM A322 ASSN STD 1ST MATERIAL RESPONSE OR ASTM A331 ASSN STD 1ST MATERIAL RESPONSE OR ASTM A322 ASSN STD 2ND MATERIAL RESPONSE OR ASTM A331 ASSN STD 2ND MATERIAL RESPONSE OR ASTM A322 ASSN STD 3RD MATERIAL RESPONSE OR ASTM A331 ASSN STD 3RD MATERIAL RESPONSE OR ASTM A322 ASSN STD 4TH MATERIAL RESPONSE OR ASTM A331 ASSN STD 4TH MATERIAL RESPONSE OVERALL
•
NOMINAL THREAD DIAMETER: 0.500 INCHES IN
•
FEATURES PROVIDED: FINISHED HEAD
TECHNICAL CHARACTERISTICS
HEAD HEIGHT0.297 INCHES NOMINAL IN
FASTENER LENGTH6.250 INCHES NOMINAL IN
THREAD LENGTH0.688 INCHES MINIMUM AND 0.812 INCHES MAXIMUM IN
HARDNESS RATING30.0 ROCKWELL C MINIMUM AND 34.0 ROCKWELL C MAXIMUM OVERALL
SHANK UNTHREADED HOLE DIAMETER0.109 INCHES NOMINAL FIRST HOLE IN
MATERIAL DOCUMENT AND CLASSIFICATIONASTM A322 ASSN STD 1ST MATERIAL RESPONSE OR ASTM A331 ASSN STD 1ST MATERIAL RESPONSE OR ASTM A322 ASSN STD 2ND MATERIAL RESPONSE OR ASTM A331 ASSN STD 2ND MATERIAL RESPONSE OR ASTM A322 ASSN STD 3RD MATERIAL RESPONSE OR ASTM A331 ASSN STD 3RD MATERIAL RESPONSE OR ASTM A322 ASSN STD 4TH MATERIAL RESPONSE OR ASTM A331 ASSN STD 4TH MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER0.500 INCHES IN
FEATURES PROVIDEDFINISHED HEAD
HEAD STYLEHEXAGON
THREAD DIRECTIONRIGHT-HAND
OTHER ITEMS IN FSC 5306 — Bolts
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5306-00-001-1276 5306-00-001-1949 5306-00-001-1988 5306-00-001-1989 5306-00-001-1990 5306-00-001-1991 5306-00-001-1993 5306-00-001-2017
SUBSTITUTES & CROSS-REFERENCES 1
5306006799855Reference document
Same NSN cross-reference
Reference document — Informative reference only
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 8756521?
8756521 is a BOLT,MACHINE.
What parts can replace 8756521?
There is 1 known substitute for 8756521: 5306006799855. Substitute compatibility should be verified for your specific system.
What is the NSN for 8756521?
8756521 is cataloged in the U.S. Government catalog under NSN 5306-00-679-9855. 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.