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NTA11551-4C — WASHER,RECESSED

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

NTA11551-4C: WASHER,RECESSED.

The WASHER,RECESSED is a the manufacturer industrial component. Key specifications include material: STEEL COMP 4130 OR STEEL COMP 8630 OR STEEL COMP 4135 OVERALL, recess_angle: 90.0 DEGREES MINIMUM AND 100.0 DEGREES MAXIMUM, hole_diameter: 0.250 INCHES MINIMUM AND 0.261 INCHES MAXIMUM IN, hardness_rating: 36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM, recess_diameter: 0.332 INCHES MINIMUM AND 0.352 INCHES MAXIMUM IN, outside_diameter: 0.475 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-042-8874, 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
NTA11551-4C
NSN: 5310-01-042-8874
FSC: 5310 — Nuts and Washers
CAGE: A0170 — LEONARDO SPA AERONAUTICS DIVISION - POMIGLIANO D'ARCO SITE (ITA)
SPECIFICATIONS
materialSTEEL COMP 4130 OR STEEL COMP 8630 OR STEEL COMP 4135 OVERALL
recess_angle90.0 DEGREES MINIMUM AND 100.0 DEGREES MAXIMUM
hole_diameter0.250 INCHES MINIMUM AND 0.261 INCHES MAXIMUM IN
hardness_rating36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM
recess_diameter0.332 INCHES MINIMUM AND 0.352 INCHES MAXIMUM IN
outside_diameter0.475 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN
style_designatorRECESSED
surface_treatmentNICKEL AND CADMIUM OVERALL
material_thickness0.057 INCHES MINIMUM AND 0.069 INCHES MAXIMUM IN
specification/standard_data81205-BACW10BP MANUFACTURERS STANDARD
material_document_and_classificationMIL-S-18729 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-18728 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-18733 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationAMS 2416 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
NSN5310-01-042-8874
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: NTA11551-4C · 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 TREATMENT DOCUMENT AND CLASSIFICATION: AMS 2416 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
•
HARDNESS RATING: 36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM
•
STYLE DESIGNATOR: RECESSED
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-18729 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-18728 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-18733 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 0.475 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN
•
MATERIAL THICKNESS: 0.057 INCHES MINIMUM AND 0.069 INCHES MAXIMUM IN
•
SPECIFICATION/STANDARD DATA: 81205-BACW10BP MANUFACTURERS STANDARD
•
RECESS DIAMETER: 0.332 INCHES MINIMUM AND 0.352 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONAMS 2416 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
HARDNESS RATING36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM
STYLE DESIGNATORRECESSED
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-18729 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-18728 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-18733 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER0.475 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN
MATERIAL THICKNESS0.057 INCHES MINIMUM AND 0.069 INCHES MAXIMUM IN
SPECIFICATION/STANDARD DATA81205-BACW10BP MANUFACTURERS STANDARD
RECESS DIAMETER0.332 INCHES MINIMUM AND 0.352 INCHES MAXIMUM IN
SURFACE TREATMENTNICKEL AND CADMIUM OVERALL
MATERIALSTEEL COMP 4130 OR STEEL COMP 8630 OR STEEL COMP 4135 OVERALL
SUBSTITUTES & CROSS-REFERENCES 1
BACW10BP4CSame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is NTA11551-4C?
NTA11551-4C is a WASHER,RECESSED.
What parts can replace NTA11551-4C?
There is 1 known substitute for NTA11551-4C: BACW10BP4C. Substitute compatibility should be verified for your specific system.
What is the NSN for NTA11551-4C?
NTA11551-4C is cataloged in the U.S. Government catalog under NSN 5310-01-042-8874. 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.