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3M348L4 — WASHER,CONCAVE

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

3M348L4: WASHER,CONCAVE.

The WASHER,CONCAVE is a the manufacturer industrial component. Key specifications include radius: 0.300 INCHES MINIMUM AND 0.305 INCHES MAXIMUM IN, material: STEEL COMP 8740 OR STEEL COMP 4037 OVERALL, hole_diameter: 0.348 INCHES MINIMUM AND 0.354 INCHES MAXIMUM IN, hardness_rating: 38.0 ROCKWELL C MINIMUM AND 43.0 ROCKWELL C MAXIMUM, outside_diameter: 0.505 INCHES MINIMUM AND 0.515 INCHES MAXIMUM IN, style_designator: CONCAVE. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-459-0866, 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
3M348L4
NSN: 5310-00-459-0866
FSC: 5310 — Nuts and Washers
CAGE: 80539 — SPS TECHNOLOGIES, LLC DBA AEROSPACE FASTENERS GROUP DIV AEROSPACE - SANTA ANA (USA)
SPECIFICATIONS
radius0.300 INCHES MINIMUM AND 0.305 INCHES MAXIMUM IN
materialSTEEL COMP 8740 OR STEEL COMP 4037 OVERALL
hole_diameter0.348 INCHES MINIMUM AND 0.354 INCHES MAXIMUM IN
hardness_rating38.0 ROCKWELL C MINIMUM AND 43.0 ROCKWELL C MAXIMUM
outside_diameter0.505 INCHES MINIMUM AND 0.515 INCHES MAXIMUM IN
style_designatorCONCAVE
surface_treatmentCADMIUM AND CHROMATE OVERALL
material_thickness0.113 INCHES MINIMUM AND 0.123 INCHES MAXIMUM IN
material_document_and_classificationMIL-S-6049 MIL SPEC 1ST MATERIAL RESPONSE OR AMS 6300 ASSN STD 2ND MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationQQ-P-416,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
NSN5310-00-459-0866
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 3M348L4 · 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: QQ-P-416,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
RADIUS: 0.300 INCHES MINIMUM AND 0.305 INCHES MAXIMUM IN
•
HARDNESS RATING: 38.0 ROCKWELL C MINIMUM AND 43.0 ROCKWELL C MAXIMUM
•
STYLE DESIGNATOR: CONCAVE
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-6049 MIL SPEC 1ST MATERIAL RESPONSE OR AMS 6300 ASSN STD 2ND MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 0.505 INCHES MINIMUM AND 0.515 INCHES MAXIMUM IN
•
MATERIAL THICKNESS: 0.113 INCHES MINIMUM AND 0.123 INCHES MAXIMUM IN
•
SURFACE TREATMENT: CADMIUM AND CHROMATE OVERALL
TECHNICAL CHARACTERISTICS
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
RADIUS0.300 INCHES MINIMUM AND 0.305 INCHES MAXIMUM IN
HARDNESS RATING38.0 ROCKWELL C MINIMUM AND 43.0 ROCKWELL C MAXIMUM
STYLE DESIGNATORCONCAVE
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-6049 MIL SPEC 1ST MATERIAL RESPONSE OR AMS 6300 ASSN STD 2ND MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER0.505 INCHES MINIMUM AND 0.515 INCHES MAXIMUM IN
MATERIAL THICKNESS0.113 INCHES MINIMUM AND 0.123 INCHES MAXIMUM IN
SURFACE TREATMENTCADMIUM AND CHROMATE OVERALL
MATERIALSTEEL COMP 8740 OR STEEL COMP 4037 OVERALL
HOLE DIAMETER0.348 INCHES MINIMUM AND 0.354 INCHES MAXIMUM IN
SUBSTITUTES & CROSS-REFERENCES 3
TLN1020L4WSame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
TLN1021-4WSame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
6073-04Reference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusCancelled· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 3M348L4?
3M348L4 is a WASHER,CONCAVE.
What parts can replace 3M348L4?
There are 3 known substitutes for 3M348L4: TLN1020L4W, TLN1021-4W, 6073-04. Substitute compatibility should be verified for your specific system.
What is the NSN for 3M348L4?
3M348L4 is cataloged in the U.S. Government catalog under NSN 5310-00-459-0866. 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.