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K19701-4 — WASHER,CONCAVE

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

K19701-4: 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: 0.358 INCHES MINIMUM AND 0.364 INCHES MAXIMUM IN, hardness_rating: 38.0 ROCKWELL C MINIMUM AND 44.0 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 5310-01-291-4017, 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
K19701-4
NSN: 5310-01-291-4017
FSC: 5310 — Nuts and Washers
CAGE: 15653 — HOWMET GLOBAL FASTENING SYSTEMS INC (USA)
SPECIFICATIONS
radius0.300 INCHES MINIMUM AND 0.305 INCHES MAXIMUM IN
materialSTEEL COMP 8740 OR STEEL COMP 4037 OVERALL
hole_diameter0.358 INCHES MINIMUM AND 0.364 INCHES MAXIMUM IN
hardness_rating38.0 ROCKWELL C MINIMUM AND 44.0 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 AND MIL-S-8695 MIL SPEC 2ND MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationQQ-P-416 TY2 CL2 FED SPEC 1ST TREATMENT RESPONSE OVERALL
NSN5310-01-291-4017
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: K19701-4 · 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 TY2 CL2 FED SPEC 1ST TREATMENT RESPONSE OVERALL
•
RADIUS: 0.300 INCHES MINIMUM AND 0.305 INCHES MAXIMUM IN
•
HARDNESS RATING: 38.0 ROCKWELL C MINIMUM AND 44.0 ROCKWELL C MAXIMUM
•
STYLE DESIGNATOR: CONCAVE
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-6049 MIL SPEC 1ST MATERIAL RESPONSE AND MIL-S-8695 MIL SPEC 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 TY2 CL2 FED SPEC 1ST TREATMENT RESPONSE OVERALL
RADIUS0.300 INCHES MINIMUM AND 0.305 INCHES MAXIMUM IN
HARDNESS RATING38.0 ROCKWELL C MINIMUM AND 44.0 ROCKWELL C MAXIMUM
STYLE DESIGNATORCONCAVE
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-6049 MIL SPEC 1ST MATERIAL RESPONSE AND MIL-S-8695 MIL SPEC 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 DIAMETER0.358 INCHES MINIMUM AND 0.364 INCHES MAXIMUM IN
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
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is K19701-4?
K19701-4 is a WASHER,CONCAVE.
What is the NSN for K19701-4?
K19701-4 is cataloged in the U.S. Government catalog under NSN 5310-01-291-4017. 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.