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Technical Data Sheet
PartsTable / COMPONENT / MS51957-21B
MS51957-21B ✓ 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 SCREW,MACHINE is a the manufacturer industrial component. Key specifications include head_style: PAN, head_height: 0.070 INCHES MINIMUM AND 0.080 INCHES MAXIMUM IN, thread_class: 2A A, head_diameter: 0.205 INCHES MINIMUM AND 0.219 INCHES MAXIMUM IN, thread_length: 0.919 INCHES MINIMUM AND 1.000 INCHES MAXIMUM IN, screw_material: STEEL CORROSION RESISTING OR STEEL. This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5305-00-419-0874, 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
MS51957-21B
NSN: 5305-00-419-0874
FSC: 5305
CAGE: 96906 — MILITARY STANDARDS PROMULGATED BY MILITARY DEPARTMENTS UNDER AUTHORITY OF DEFENSE STANDARDIZATION MANUAL 4120 3-M
SPECIFICATIONS
head_stylePAN
head_height0.070 INCHES MINIMUM AND 0.080 INCHES MAXIMUM IN
thread_class2A A
head_diameter0.205 INCHES MINIMUM AND 0.219 INCHES MAXIMUM IN
thread_length0.919 INCHES MINIMUM AND 1.000 INCHES MAXIMUM IN
screw_materialSTEEL CORROSION RESISTING OR STEEL
fastener_length0.969 INCHES MINIMUM AND 1.000 INCHES MAXIMUM IN
thread_directionRIGHT-HAND
internal_drive_styleCROSS RECESS TYPE 1
nominal_thread_diameter0.112 INCHES IN
screw_surface_treatmentOXIDE
minimum_tensile_strength80000 POUNDS PER SQUARE INCH LBS
NSN5305-00-419-0874
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: MS51957-21B · 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 SERIES DESIGNATOR: UNIFIED NATIONAL COARSE (UNC)
•
INTERNAL DRIVE STYLE: CROSS RECESS TYPE 1
•
SCREW MATERIAL: STEEL CORROSION RESISTING OR STEEL
•
HEAD STYLE: PAN
•
THREAD QUANTITY PER INCH: 40
•
SCREW SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: MIL-C-13924 CL 4 MIL SPEC SINGLE TREATMENT RESPONSE
•
THREAD DIRECTION: RIGHT-HAND
•
HEAD DIAMETER: 0.205 INCHES MINIMUM AND 0.219 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS (FLIS)
THREAD SERIES DESIGNATORUNIFIED NATIONAL COARSE (UNC)
INTERNAL DRIVE STYLECROSS RECESS TYPE 1
SCREW MATERIALSTEEL CORROSION RESISTING OR STEEL
HEAD STYLEPAN
THREAD QUANTITY PER INCH40
SCREW SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONMIL-C-13924 CL 4 MIL SPEC SINGLE TREATMENT RESPONSE
THREAD DIRECTIONRIGHT-HAND
HEAD DIAMETER0.205 INCHES MINIMUM AND 0.219 INCHES MAXIMUM IN
THREAD LENGTH0.919 INCHES MINIMUM AND 1.000 INCHES MAXIMUM IN
SCREW MATERIAL DOCUMENT AND CLASSIFICATIONQQ-S-763,300 SERIES FED SPEC 1ST MATERIAL RESPONSE OR 66,300 SERIES FED STD 1ST MATERIAL RESPONSE OR COMP 16-18 OR 18-8 ASSN STD 2ND MATERIAL RESPONSE
VERIFIED SUBSTITUTES & CROSS-REFERENCES 6
343-0141-000Interchangeable
interchangeable cross-reference
interchangeable
5M.3033.220.07Interchangeable
interchangeable cross-reference
interchangeable
FFS92Interchangeable
interchangeable cross-reference
interchangeable
418329-21Interchangeable
Same NIIN cross-reference
interchangeable
AH726-24Interchangeable
Same NIIN cross-reference
interchangeable
0418329-021Interchangeable
Same NIIN cross-reference
interchangeable
LIFECYCLE
StatusCANCELLED
Availability—
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is MS51957-21B?
MS51957-21B is a SCREW,MACHINE.
What parts can replace MS51957-21B?
There are 6 known substitutes for MS51957-21B: 343-0141-000, 5M.3033.220.07, FFS92 and 3 more. Substitute compatibility should be verified for your specific system.
Is MS51957-21B still available?
MS51957-21B is currently cancelled.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026