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187981 — THUMBSCREW

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

187981: THUMBSCREW.

The THUMBSCREW is a the manufacturer industrial component. Key specifications include material: COPPER ALLOY OVERALL, head_style: KNURLED NO. 4, head_height: 0.250 INCHES NOMINAL IN, point_style: FLAT, thread_class: 3A A, head_diameter: 0.375 INCHES NOMINAL IN.

This part is cataloged in the U.S. Government catalog under NSN 5305-00-413-7512, 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
187981
NSN: 5305-00-413-7512
FSC: 5305 — Screws
CAGE: 56232 — LOCKHEED MARTIN CORPORATION DIV RMS - MITCHEL FIELD (USA)
SPECIFICATIONS
materialCOPPER ALLOY OVERALL
head_styleKNURLED NO. 4
head_height0.250 INCHES NOMINAL IN
point_styleFLAT
thread_class3A A
head_diameter0.375 INCHES NOMINAL IN
thread_length0.750 INCHES MINIMUM IN
fastener_length1.375 INCHES NOMINAL IN
thread_directionRIGHT-HAND
surface_treatmentTIN OVERALL
nominal_thread_diameter0.190 INCHES IN
first_diameter_from_head0.125 INCHES NOMINAL IN
NSN5305-00-413-7512
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 187981 · 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: 0.250 INCHES NOMINAL IN
•
FASTENER LENGTH: 1.375 INCHES NOMINAL IN
•
THREAD LENGTH: 0.750 INCHES MINIMUM IN
•
FIRST DIAMETER FROM HEAD: 0.125 INCHES NOMINAL IN
•
NOMINAL THREAD DIAMETER: 0.190 INCHES IN
•
HEAD STYLE: KNURLED NO. 4
•
THREAD DIRECTION: RIGHT-HAND
•
POINT STYLE: FLAT
TECHNICAL CHARACTERISTICS
HEAD HEIGHT0.250 INCHES NOMINAL IN
FASTENER LENGTH1.375 INCHES NOMINAL IN
THREAD LENGTH0.750 INCHES MINIMUM IN
FIRST DIAMETER FROM HEAD0.125 INCHES NOMINAL IN
NOMINAL THREAD DIAMETER0.190 INCHES IN
HEAD STYLEKNURLED NO. 4
THREAD DIRECTIONRIGHT-HAND
POINT STYLEFLAT
DISTANCE FROM LARGEST BEARING SURFACE OF HEAD TO END OF FIRST DIAMETER0.500 INCHES NOMINAL IN
SURFACE TREATMENTTIN OVERALL
OTHER ITEMS IN FSC 5305 — Screws
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5305-00-001-5016 5305-00-001-9160 5305-00-001-9629 5305-00-001-9742 5305-00-001-9768 5305-00-003-4306 5305-00-003-6694 5305-00-003-6753
SUBSTITUTES & CROSS-REFERENCES

No substitute or cross-reference records for this part.

LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Terminal item — stock exhausted; no further procurementNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 187981?
187981 is a THUMBSCREW.
What is the NSN for 187981?
187981 is cataloged in the U.S. Government catalog under NSN 5305-00-413-7512. 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.