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Technical Data Sheet
PartsTable / COMPONENT / MIL-B-857A
MIL-B-857A ✓ Verified by PartsTable
— · BOLT SCREW
WHAT YOU NEED TO KNOW
Grade/class stamped on head determines strength Metric and imperial threads look similar — measure pitch
Verify thread pitch — metric != imperial
PRODUCT OVERVIEW

The BOLT,MACHINE is a the manufacturer industrial component. Key specifications include criticality_code_justification: ZZZY, reference_number_differentiating_characteristics: MATERIAL WILL BE IN ACCORDANCE WITH NAVICP MECH; ACTIVITY HX QUALITY CONTROL, MANUFACTURING AND TESTING SPECIFICATIONS.. This product is currently in active production with full OEM support.

This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5306-00-174-4166, 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
MIL-B-857A
NSN: 5306-00-174-4166
FSC: 5306
CAGE: 81349 — MILITARY SPECIFICATIONS PROMULGATED BY MILITARY DEPARTMENTS/AGENCIES UNDER AUTHORITY OF DEFENSE STANDARDIZATION MANUAL 4120 3-M
SPECIFICATIONS
criticality_code_justificationZZZY
reference_number_differentiating_characteristicsMATERIAL WILL BE IN ACCORDANCE WITH NAVICP MECH; ACTIVITY HX QUALITY CONTROL, MANUFACTURING AND TESTING SPECIFICATIONS.
NSN5306-00-174-4166
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: MIL-B-857A · 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
•
THREAD QUANTITY PER INCH: 13
•
FEATURES PROVIDED: FINISHED HEAD
•
HEAD HEIGHT: 0.312 INCHES NOMINAL IN
•
SPECIFICATION/STANDARD DATA: 81349--1222RN8C216GFNZE GOVERNMENT SPECIFICATION
•
HARDNESS RATING: 23.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM OVERALL
•
WIDTH BETWEEN FLATS: 0.725 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN
•
FASTENER LENGTH: 1.000 INCHES NOMINAL IN
•
MINIMUM TENSILE STRENGTH: 120000 POUNDS PER SQUARE INCH LBS
TECHNICAL CHARACTERISTICS (FLIS)
THREAD QUANTITY PER INCH13
FEATURES PROVIDEDFINISHED HEAD
HEAD HEIGHT0.312 INCHES NOMINAL IN
SPECIFICATION/STANDARD DATA81349--1222RN8C216GFNZE GOVERNMENT SPECIFICATION
HARDNESS RATING23.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM OVERALL
WIDTH BETWEEN FLATS0.725 INCHES MINIMUM AND 0.750 INCHES MAXIMUM IN
FASTENER LENGTH1.000 INCHES NOMINAL IN
MINIMUM TENSILE STRENGTH120000 POUNDS PER SQUARE INCH LBS
NOMINAL THREAD DIAMETER0.500 INCHES IN
THREAD DIRECTIONRIGHT-HAND
VERIFIED SUBSTITUTES & CROSS-REFERENCES 19
MILB857AUpgraded Successor
successor cross-reference
successor
M1222RN12C48GFNNUpgraded Successor
successor cross-reference
successor
MIL-S-1222Upgraded Successor
successor cross-reference
successor
MIL-DTL-1222Upgraded Successor
successor cross-reference
successor
306-40172Upgraded Successor
successor cross-reference
successor
1D4703Upgraded Successor
successor cross-reference
successor
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is MIL-B-857A?
MIL-B-857A is a BOLT,MACHINE.
What parts can replace MIL-B-857A?
There are 19 known substitutes for MIL-B-857A: MILB857A, M1222RN12C48GFNN, MIL-S-1222 and 16 more. Substitute compatibility should be verified for your specific system.
What is the NSN for MIL-B-857A?
MIL-B-857A is cataloged in the Federal Logistics Information System (FLIS) under NSN 5306-00-174-4166. This indicates validated use in U.S. government and defense supply chains.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026