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LH13374-40LH — NUT,SELF-LOCKING,EXTENDED WASHER

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

LH13374-40LH: NUT,SELF-LOCKING,EXTENDED WASHER.

NUT,SELF-LOCKING,EXTENDED WASHER. Key specifications include material: STEEL COMP 4340 OR STEEL COMP 8740 OR STEEL COMP 4037 OVERALL, nut_style: HEXAGON, thread_class: 3B, thread_series: UNIFIED NATIONAL JOINT FINE (UNJF), overall_height: 0.267 INCHES MINIMUM AND 0.282 INCHES MAXIMUM IN, hardness_rating: 49.0 ROCKWELL C MAXIMUM. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-349-9416, 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
LH13374-40LH
NSN: 5310-01-349-9416
FSC: 5310 — Nuts and Washers
CAGE: 72962 — HARVARD INDUSTRIES INC (USA)
SPECIFICATIONS
materialSTEEL COMP 4340 OR STEEL COMP 8740 OR STEEL COMP 4037 OVERALL
nut_styleHEXAGON
thread_class3B
thread_seriesUNIFIED NATIONAL JOINT FINE (UNJF)
overall_height0.267 INCHES MINIMUM AND 0.282 INCHES MAXIMUM IN
hardness_rating49.0 ROCKWELL C MAXIMUM
locking_featurePREVAILING TORQUE ALL METAL DESIGN
thread_directionLEFT-HAND
washer_thickness0.030 INCHES MINIMUM IN
surface_treatmentCADMIUM OVERALL
width_across_flats0.430 INCHES MINIMUM AND 0.440 INCHES MAXIMUM IN
nominal_thread_size0.375 INCHES IN
NSN5310-01-349-9416
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: LH13374-40LH · 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
•
WASHER OUTSIDE DIAMETER: 0.620 INCHES MAXIMUM IN
•
WIDTH ACROSS FLATS: 0.430 INCHES MINIMUM AND 0.440 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416, TYPE II, CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD SERIES: UNIFIED NATIONAL JOINT FINE (UNJF)
•
HARDNESS RATING: 49.0 ROCKWELL C MAXIMUM
•
WASHER THICKNESS: 0.030 INCHES MINIMUM IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 6415 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 6414 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 6322 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 6300 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT0.267 INCHES MINIMUM AND 0.282 INCHES MAXIMUM IN
WASHER OUTSIDE DIAMETER0.620 INCHES MAXIMUM IN
WIDTH ACROSS FLATS0.430 INCHES MINIMUM AND 0.440 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416, TYPE II, CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD SERIESUNIFIED NATIONAL JOINT FINE (UNJF)
HARDNESS RATING49.0 ROCKWELL C MAXIMUM
WASHER THICKNESS0.030 INCHES MINIMUM IN
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 6415 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 6414 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 6322 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 6300 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
THREAD DIRECTIONLEFT-HAND
NOMINAL THREAD SIZE0.375 INCHES 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 2
3D0106-6Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LH13374-6LHReference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is LH13374-40LH?
LH13374-40LH is a NUT,SELF-LOCKING,EXTENDED WASHER.
What parts can replace LH13374-40LH?
There are 2 known substitutes for LH13374-40LH: 3D0106-6, LH13374-6LH. Substitute compatibility should be verified for your specific system.
What is the NSN for LH13374-40LH?
LH13374-40LH is cataloged in the U.S. Government catalog under NSN 5310-01-349-9416. 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.