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MM891C4 — WASHER,RECESSED

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

MM891C4: WASHER,RECESSED.

The WASHER,RECESSED is a the manufacturer industrial component. Key specifications include material: NICKEL ALLOY 718 OVERALL, recess_angle: 40.0 DEGREES MINIMUM AND 50.0 DEGREES MAXIMUM, hole_diameter: 0.251 INCHES MINIMUM AND 0.255 INCHES MAXIMUM IN, hardness_rating: 36.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM, recess_diameter: 0.310 INCHES MINIMUM AND 0.320 INCHES MAXIMUM IN, outside_diameter: 0.460 INCHES MINIMUM AND 0.470 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-507-9305, 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
MM891C4
NSN: 5310-01-507-9305
FSC: 5310 — Nuts and Washers
CAGE: 58009 — MOELLER MANUFACTURING & SUPPLY, LLC (USA)
SPECIFICATIONS
materialNICKEL ALLOY 718 OVERALL
recess_angle40.0 DEGREES MINIMUM AND 50.0 DEGREES MAXIMUM
hole_diameter0.251 INCHES MINIMUM AND 0.255 INCHES MAXIMUM IN
hardness_rating36.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM
recess_diameter0.310 INCHES MINIMUM AND 0.320 INCHES MAXIMUM IN
outside_diameter0.460 INCHES MINIMUM AND 0.470 INCHES MAXIMUM IN
style_designatorRECESSED
surface_treatmentPASSIVATE OVERALL
material_thickness0.057 INCHES MINIMUM AND 0.069 INCHES MAXIMUM IN
material_document_and_classificationAMS 5596 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5597 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5662 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
NSN5310-01-507-9305
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: MM891C4 · 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-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
HARDNESS RATING: 36.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM
•
STYLE DESIGNATOR: RECESSED
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 5596 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5597 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5662 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 0.460 INCHES MINIMUM AND 0.470 INCHES MAXIMUM IN
•
MATERIAL THICKNESS: 0.057 INCHES MINIMUM AND 0.069 INCHES MAXIMUM IN
•
RECESS DIAMETER: 0.310 INCHES MINIMUM AND 0.320 INCHES MAXIMUM IN
•
SURFACE TREATMENT: PASSIVATE OVERALL
TECHNICAL CHARACTERISTICS
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
HARDNESS RATING36.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM
STYLE DESIGNATORRECESSED
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 5596 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5597 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5662 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER0.460 INCHES MINIMUM AND 0.470 INCHES MAXIMUM IN
MATERIAL THICKNESS0.057 INCHES MINIMUM AND 0.069 INCHES MAXIMUM IN
RECESS DIAMETER0.310 INCHES MINIMUM AND 0.320 INCHES MAXIMUM IN
SURFACE TREATMENTPASSIVATE OVERALL
MATERIALNICKEL ALLOY 718 OVERALL
HOLE DIAMETER0.251 INCHES MINIMUM AND 0.255 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 1
03A280C4Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
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 MM891C4?
MM891C4 is a WASHER,RECESSED.
What parts can replace MM891C4?
There is 1 known substitute for MM891C4: 03A280C4. Substitute compatibility should be verified for your specific system.
What is the NSN for MM891C4?
MM891C4 is cataloged in the U.S. Government catalog under NSN 5310-01-507-9305. 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.