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1881-178A — WASHER,KEY

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

1881-178A: WASHER,KEY.

The WASHER,KEY is a the manufacturer industrial component. Key specifications include material: STEEL COMP 4130 OVERALL, hole_diameter: 1.020 INCHES NOMINAL IN, surface_finish: 125.0 MICROINCHES ALL SURFACES, outside_diameter: 1.560 INCHES NOMINAL IN, special_features: HEAT TREAT 90,000 PSI-UTS PER MIL-H-6875, style_designator: KEY. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-175-6078, 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
1881-178A
NSN: 5310-01-175-6078
FSC: 5310 — Nuts and Washers
CAGE: 6K4C8 — GOODRICH CORPORATION (USA)
SPECIFICATIONS
materialSTEEL COMP 4130 OVERALL
hole_diameter1.020 INCHES NOMINAL IN
surface_finish125.0 MICROINCHES ALL SURFACES
outside_diameter1.560 INCHES NOMINAL IN
special_featuresHEAT TREAT 90,000 PSI-UTS PER MIL-H-6875
style_designatorKEY
surface_treatmentPRIMER AND ENAMEL AND CADMIUM OVERALL
material_thickness0.120 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN
internal_key_quantity1
internal_straight_key_width0.179 INCHES MINIMUM AND 0.184 INCHES MAXIMUM IN
material_document_and_classificationMIL-S-6758 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationMIL-P-23377 MIL SPEC 1ST TREATMENT RESPONSE AND FED-STD-595 COLOR 17875 FED STD 2ND TREATMENT RESPONSE AND QQ-P-416 TY 2 CL 1 FED SPEC 3RD TREATMENT RESPONSE OVERALL
NSN5310-01-175-6078
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 1881-178A · 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: 0.179 INCHES MINIMUM AND 0.184 INCHES MAXIMUM IN
•
DISTANCE FROM CENTERLINE TO TOP OF INTERNAL KEY: 0.395 INCHES NOMINAL IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: MIL-P-23377 MIL SPEC 1ST TREATMENT RESPONSE AND FED-STD-595 COLOR 17875 FED STD 2ND TREATMENT RESPONSE AND QQ-P-416 TY 2 CL 1 FED SPEC 3RD TREATMENT RESPONSE OVERALL
•
STYLE DESIGNATOR: KEY
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-6758 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 1.560 INCHES NOMINAL IN
•
MATERIAL THICKNESS: 0.120 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
SURFACE FINISH125.0 MICROINCHES ALL SURFACES
INTERNAL STRAIGHT KEY WIDTH0.179 INCHES MINIMUM AND 0.184 INCHES MAXIMUM IN
DISTANCE FROM CENTERLINE TO TOP OF INTERNAL KEY0.395 INCHES NOMINAL IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONMIL-P-23377 MIL SPEC 1ST TREATMENT RESPONSE AND FED-STD-595 COLOR 17875 FED STD 2ND TREATMENT RESPONSE AND QQ-P-416 TY 2 CL 1 FED SPEC 3RD TREATMENT RESPONSE OVERALL
STYLE DESIGNATORKEY
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-6758 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER1.560 INCHES NOMINAL IN
MATERIAL THICKNESS0.120 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN
SPECIAL FEATURESHEAT TREAT 90,000 PSI-UTS PER MIL-H-6875
SURFACE TREATMENTPRIMER AND ENAMEL AND CADMIUM 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 1881-178A?
1881-178A is a WASHER,KEY.
What is the NSN for 1881-178A?
1881-178A is cataloged in the U.S. Government catalog under NSN 5310-01-175-6078. 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.