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A51G20121-13 — WASHER,KEY

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

A51G20121-13: WASHER,KEY.

The WASHER,KEY is a the manufacturer industrial component. Key specifications include material: STEEL COMP 4130 OVERALL, hole_diameter: 0.470 INCHES MINIMUM AND 0.480 INCHES MAXIMUM IN, hardness_rating: 33.0 ROCKWELL C MINIMUM AND 37.0 ROCKWELL C MAXIMUM, special_features: INTERNAL KEY LOCATED 135 DEG FROM EXTERNAL KEY, style_designator: KEY, surface_treatment: CADMIUM OVERALL. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-003-6542, 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
A51G20121-13
NSN: 5310-00-003-6542
FSC: 5310 — Nuts and Washers
CAGE: 79RG9 — NORTHROP GRUMMAN SYSTEMS CORPORATION (USA)
SPECIFICATIONS
materialSTEEL COMP 4130 OVERALL
hole_diameter0.470 INCHES MINIMUM AND 0.480 INCHES MAXIMUM IN
hardness_rating33.0 ROCKWELL C MINIMUM AND 37.0 ROCKWELL C MAXIMUM
special_featuresINTERNAL KEY LOCATED 135 DEG FROM EXTERNAL KEY
style_designatorKEY
surface_treatmentCADMIUM OVERALL
material_thickness0.038 INCHES NOMINAL IN
external_prebent_key_width0.105 INCHES MINIMUM AND 0.115 INCHES MAXIMUM IN
external_prebent_key_length0.045 INCHES MINIMUM AND 0.055 INCHES MAXIMUM IN
internal_straight_key_width0.059 INCHES MINIMUM AND 0.065 INCHES MAXIMUM IN
overall_distance_including_keys0.738 INCHES MINIMUM AND 0.764 INCHES MAXIMUM IN
material_document_and_classificationMIL-S-18729 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
NSN5310-00-003-6542
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: A51G20121-13 · 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
•
INTERNAL STRAIGHT KEY WIDTH: 0.059 INCHES MINIMUM AND 0.065 INCHES MAXIMUM IN
•
DISTANCE FROM CENTERLINE TO TOP OF INTERNAL KEY: 0.193 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: MIL-C-8837,TYPE2,CLASS1 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
•
DISTANCE FROM CENTERLINE TO INSIDE OF PREBENT KEY: 0.351 INCHES MINIMUM AND 0.367 INCHES MAXIMUM IN
•
EXTERNAL PREBENT KEY LENGTH: 0.045 INCHES MINIMUM AND 0.055 INCHES MAXIMUM IN
•
OVERALL DISTANCE INCLUDING KEYS: 0.738 INCHES MINIMUM AND 0.764 INCHES MAXIMUM IN
•
HARDNESS RATING: 33.0 ROCKWELL C MINIMUM AND 37.0 ROCKWELL C MAXIMUM
•
STYLE DESIGNATOR: KEY
TECHNICAL CHARACTERISTICS
INTERNAL STRAIGHT KEY WIDTH0.059 INCHES MINIMUM AND 0.065 INCHES MAXIMUM IN
DISTANCE FROM CENTERLINE TO TOP OF INTERNAL KEY0.193 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONMIL-C-8837,TYPE2,CLASS1 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
DISTANCE FROM CENTERLINE TO INSIDE OF PREBENT KEY0.351 INCHES MINIMUM AND 0.367 INCHES MAXIMUM IN
EXTERNAL PREBENT KEY LENGTH0.045 INCHES MINIMUM AND 0.055 INCHES MAXIMUM IN
OVERALL DISTANCE INCLUDING KEYS0.738 INCHES MINIMUM AND 0.764 INCHES MAXIMUM IN
HARDNESS RATING33.0 ROCKWELL C MINIMUM AND 37.0 ROCKWELL C MAXIMUM
STYLE DESIGNATORKEY
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-18729 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
MATERIAL THICKNESS0.038 INCHES NOMINAL IN
OTHER ITEMS IN FSC 5310 — Nuts and Washers
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5310-00-001-5340 5310-00-004-4584 5310-00-004-5157 5310-00-004-7045 5310-00-004-7046 5310-00-005-4375 5310-00-006-8067 5310-00-007-2907
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 A51G20121-13?
A51G20121-13 is a WASHER,KEY.
What is the NSN for A51G20121-13?
A51G20121-13 is cataloged in the U.S. Government catalog under NSN 5310-00-003-6542. 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.