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1881B255 — WASHER,KEY

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

1881B255: WASHER,KEY.

The WASHER,KEY is a the manufacturer industrial component. Key specifications include material: STEEL COMP 4340 OVERALL, hole_diameter: 3.795 INCHES NOMINAL IN, surface_finish: 125.0 MICROINCHES ALL SURFACES, outside_diameter: 4.125 INCHES NOMINAL IN, style_designator: KEY, surface_treatment: CHROMIUM OVERALL. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-187-3922, 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
1881B255
NSN: 5310-01-187-3922
FSC: 5310 — Nuts and Washers
CAGE: 6K4C8 — GOODRICH CORPORATION (USA)
SPECIFICATIONS
materialSTEEL COMP 4340 OVERALL
hole_diameter3.795 INCHES NOMINAL IN
surface_finish125.0 MICROINCHES ALL SURFACES
outside_diameter4.125 INCHES NOMINAL IN
style_designatorKEY
surface_treatmentCHROMIUM OVERALL
material_thickness0.280 INCHES NOMINAL IN
internal_key_quantity2
internal_straight_key_width0.490 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN
material_document_and_classificationMIL-S-8844,CLASS 1 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationQQ-C-320,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
distance_from_centerline_to_top_of_internal_key1.381 INCHES MINIMUM AND 1.386 INCHES MAXIMUM IN
NSN5310-01-187-3922
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 1881B255 · OEM ⚠ VERIFY BEFORE ORDERING Grade matters for torque spec — don't mix grades. A Grade 5 nut on a Grade 8 bolt weakens the joint. Lock nuts, wing nuts, and castle nuts are NOT interchangeable with standard hex ✓ BROKER TIP Match nut to bolt thread class and material. Stainless bolt + zinc nut = galvanic corrosion. Always verify finish matches (plain, zinc, hot-dip galvanized) PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
SURFACE FINISH: 125.0 MICROINCHES ALL SURFACES
•
INTERNAL STRAIGHT KEY WIDTH: 0.490 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN
•
DISTANCE FROM CENTERLINE TO TOP OF INTERNAL KEY: 1.381 INCHES MINIMUM AND 1.386 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-C-320,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
STYLE DESIGNATOR: KEY
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-8844,CLASS 1 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 4.125 INCHES NOMINAL IN
•
MATERIAL THICKNESS: 0.280 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
SURFACE FINISH125.0 MICROINCHES ALL SURFACES
INTERNAL STRAIGHT KEY WIDTH0.490 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN
DISTANCE FROM CENTERLINE TO TOP OF INTERNAL KEY1.381 INCHES MINIMUM AND 1.386 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-C-320,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
STYLE DESIGNATORKEY
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-8844,CLASS 1 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER4.125 INCHES NOMINAL IN
MATERIAL THICKNESS0.280 INCHES NOMINAL IN
SURFACE TREATMENTCHROMIUM OVERALL
MATERIALSTEEL COMP 4340 OVERALL
OTHER ITEMS IN FSC 5310 — Nuts and Washers
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5310-00-000-0040 5310-00-000-0077 5310-00-000-0079 5310-00-000-1146 5310-00-000-3815 5310-00-000-4532 5310-00-000-4540
SUBSTITUTES & CROSS-REFERENCES

No substitute or cross-reference records for this part.

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 1881B255?
1881B255 is a WASHER,KEY.
What is the NSN for 1881B255?
1881B255 is cataloged in the U.S. Government catalog under NSN 5310-01-187-3922. 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.