PartsTable
Technical Data Sheet
Download PDF

K19701P4 — WASHER,CONCAVE

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

K19701P4: WASHER,CONCAVE.

The WASHER,CONCAVE is a the manufacturer industrial component. Key specifications include radius: 0.300 INCHES MAXIMUM IN, material: STEEL COMP 8740 OR STEEL COMP 8630 OR STEEL COMP 4130 OVERALL, recess_depth: 0.051 INCHES NOMINAL IN, hole_diameter: 0.348 INCHES MINIMUM AND 0.354 INCHES MAXIMUM IN, surface_finish: 63.0 MICROINCHES COUNTERBORE WALL, hardness_rating: 38.0 ROCKWELL C MINIMUM AND 44.0 ROCKWELL C MAXIMUM. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-434-5879, 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
K19701P4
NSN: 5310-01-434-5879
FSC: 5310 — Nuts and Washers
CAGE: 15653 — HOWMET GLOBAL FASTENING SYSTEMS INC (USA)
SPECIFICATIONS
radius0.300 INCHES MAXIMUM IN
materialSTEEL COMP 8740 OR STEEL COMP 8630 OR STEEL COMP 4130 OVERALL
recess_depth0.051 INCHES NOMINAL IN
hole_diameter0.348 INCHES MINIMUM AND 0.354 INCHES MAXIMUM IN
surface_finish63.0 MICROINCHES COUNTERBORE WALL
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
specification/standard_data81205-BACW10AU MANUFACTURERS STANDARD
material_document_and_classificationMIL-S-6049 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-6050 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-6758 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
NSN5310-01-434-5879
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: K19701P4 · 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: 63.0 MICROINCHES COUNTERBORE WALL
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416, TY 2, CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
RADIUS: 0.300 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 OR MIL-S-6050 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-6758 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 0.505 INCHES MINIMUM AND 0.515 INCHES MAXIMUM IN
•
RECESS DEPTH: 0.051 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
SURFACE FINISH63.0 MICROINCHES COUNTERBORE WALL
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416, TY 2, CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
RADIUS0.300 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 OR MIL-S-6050 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-6758 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER0.505 INCHES MINIMUM AND 0.515 INCHES MAXIMUM IN
RECESS DEPTH0.051 INCHES NOMINAL IN
MATERIAL THICKNESS0.113 INCHES MINIMUM AND 0.123 INCHES MAXIMUM IN
SPECIFICATION/STANDARD DATA81205-BACW10AU MANUFACTURERS STANDARD
SUBSTITUTES & CROSS-REFERENCES 2
53488W-428Reference document
Same NSN cross-reference
Reference document — Secondary reference
BACW10AU4Same 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
Ready to buy K19701P4?
Compare prices from verified sellers on eBay
Buy on eBay →
As an eBay Partner, PartsTable may earn a commission. Your price is not affected.
FREQUENTLY ASKED QUESTIONS
What is K19701P4?
K19701P4 is a WASHER,CONCAVE.
What parts can replace K19701P4?
There are 2 known substitutes for K19701P4: 53488W-428, BACW10AU4. Substitute compatibility should be verified for your specific system.
What is the NSN for K19701P4?
K19701P4 is cataloged in the U.S. Government catalog under NSN 5310-01-434-5879. This indicates validated use in U.S. government and defense supply chains.
Community Feedback
Leave a Comment
Comments are reviewed before appearing. You will receive an email to verify before your comment appears.

Request a Quote — K19701P4

✓ 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.