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N50251A — THUMBSCREW

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

N50251A: THUMBSCREW.

The THUMBSCREW is a the manufacturer industrial component. Key specifications include material: STEEL OVERALL, head_style: THUMB NO. 4, head_height: 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN, point_style: FLAT, thread_class: 2A A, thread_length: 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN.

This part is cataloged in the U.S. Government catalog under NSN 5305-00-550-1507, 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
N50251A
NSN: 5305-00-550-1507
FSC: 5305 — Screws
CAGE: 56442 — DIAMOND REO TRUCK CO (USA)
SPECIFICATIONS
materialSTEEL OVERALL
head_styleTHUMB NO. 4
head_height0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
point_styleFLAT
thread_class2A A
thread_length0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
fastener_length0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
thread_directionRIGHT-HAND
width_between_flats0.865 INCHES MINIMUM AND 0.885 INCHES MAXIMUM IN
nominal_thread_diameter0.250 INCHES IN
thread_quantity_per_inch20
thread_series_designatorUNIFIED NATIONAL COARSE (UNC)
NSN5305-00-550-1507
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: N50251A · 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: 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
•
FASTENER LENGTH: 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
•
THREAD LENGTH: 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
•
NOMINAL THREAD DIAMETER: 0.250 INCHES IN
•
HEAD STYLE: THUMB NO. 4
•
THREAD DIRECTION: RIGHT-HAND
•
POINT STYLE: FLAT
•
WIDTH BETWEEN FLATS: 0.865 INCHES MINIMUM AND 0.885 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
HEAD HEIGHT0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
FASTENER LENGTH0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
THREAD LENGTH0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
NOMINAL THREAD DIAMETER0.250 INCHES IN
HEAD STYLETHUMB NO. 4
THREAD DIRECTIONRIGHT-HAND
POINT STYLEFLAT
WIDTH BETWEEN FLATS0.865 INCHES MINIMUM AND 0.885 INCHES MAXIMUM IN
THREAD CLASS2A A
THREAD QUANTITY PER INCH20
SUBSTITUTES & CROSS-REFERENCES 1
389297Reference 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 N50251A?
N50251A is a THUMBSCREW.
What parts can replace N50251A?
There is 1 known substitute for N50251A: 389297. Substitute compatibility should be verified for your specific system.
What is the NSN for N50251A?
N50251A is cataloged in the U.S. Government catalog under NSN 5305-00-550-1507. 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.