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MB138 — NUT,PLAIN,ROUND

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

MB138: NUT,PLAIN,ROUND.

The NUT,PLAIN,ROUND is a the manufacturer industrial component. Key specifications include material: COPPER ALLOY 464 OVERALL, nut_style: ROUND, nut_diameter: 0.406 INCHES NOMINAL IN, thread_class: 2B, nut_thickness: 0.203 INCHES NOMINAL IN, thread_series: UNEF. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-474-7878, 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
MB138
NSN: 5310-00-474-7878
FSC: 5310 — Nuts and Washers
CAGE: 17431 — ILLINOIS TOOL WORKS INC. (USA)
SPECIFICATIONS
materialCOPPER ALLOY 464 OVERALL
nut_styleROUND
nut_diameter0.406 INCHES NOMINAL IN
thread_class2B
nut_thickness0.203 INCHES NOMINAL IN
thread_seriesUNEF
special_featuresREDUCED ID ONE END 0.143 IN. DIA IN
thread_directionRIGHT-HAND
surface_treatmentNICKEL OVERALL
nominal_thread_size0.312 INCHES IN
thread_quantity_per_inch32
material_document_and_classificationSAE 73 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
NSN5310-00-474-7878
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: MB138 · 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
•
THREAD SERIES: UNEF
•
MATERIAL DOCUMENT AND CLASSIFICATION: SAE 73 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
THREAD DIRECTION: RIGHT-HAND
•
NOMINAL THREAD SIZE: 0.312 INCHES IN
•
NUT DIAMETER: 0.406 INCHES NOMINAL IN
•
NUT THICKNESS: 0.203 INCHES NOMINAL IN
•
SURFACE TREATMENT: NICKEL OVERALL
TECHNICAL CHARACTERISTICS
THREAD SERIESUNEF
MATERIAL DOCUMENT AND CLASSIFICATIONSAE 73 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
THREAD DIRECTIONRIGHT-HAND
NOMINAL THREAD SIZE0.312 INCHES IN
NUT DIAMETER0.406 INCHES NOMINAL IN
NUT THICKNESS0.203 INCHES NOMINAL IN
SPECIAL FEATURESREDUCED ID ONE END 0.143 IN. DIA IN
SURFACE TREATMENTNICKEL OVERALL
NUT STYLEROUND
THREAD CLASS2B
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
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is MB138?
MB138 is a NUT,PLAIN,ROUND.
What is the NSN for MB138?
MB138 is cataloged in the U.S. Government catalog under NSN 5310-00-474-7878. 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.