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ST3M787-3 — NUT,SELF-LOCKING,EXTENDED WASHER

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

ST3M787-3: NUT,SELF-LOCKING,EXTENDED WASHER.

NUT,SELF-LOCKING,EXTENDED WASHER. Key specifications include material: IRON ALLOY 660 OVERALL, nut_style: SLOTTED HEXAGON, lubrication: DRY FILM LUBRICANT, temp_rating: 450.0 FAHRENHEIT NOMINAL DEGF, thread_class: 3B, thread_series: UNIFIED NATIONAL JOINT FINE (UNJF). This part is cataloged in the U.S.

Government catalog under NSN 5310-01-181-5045, 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
ST3M787-3
NSN: 5310-01-181-5045
FSC: 5310 — Nuts and Washers
CAGE: 76301 — THE BOEING COMPANY DIV DEFENSE (USA)
SPECIFICATIONS
materialIRON ALLOY 660 OVERALL
nut_styleSLOTTED HEXAGON
lubricationDRY FILM LUBRICANT
temp_rating450.0 FAHRENHEIT NOMINAL DEGF
thread_class3B
thread_seriesUNIFIED NATIONAL JOINT FINE (UNJF)
overall_height0.235 INCHES MINIMUM AND 0.265 INCHES MAXIMUM IN
locking_featurePREVAILING TORQUE ALL METAL DESIGN
thread_directionRIGHT-HAND
washer_thickness0.025 INCHES NOMINAL IN
surface_treatmentPASSIVATE OVERALL
width_across_flats0.243 INCHES MINIMUM AND 0.252 INCHES MAXIMUM IN
NSN5310-01-181-5045
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: ST3M787-3 · 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
•
LUBRICATION: DRY FILM LUBRICANT
•
WASHER OUTSIDE DIAMETER: 0.325 INCHES MAXIMUM IN
•
WIDTH ACROSS FLATS: 0.243 INCHES MINIMUM AND 0.252 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD SERIES: UNIFIED NATIONAL JOINT FINE (UNJF)
•
TEMP RATING: 450.0 FAHRENHEIT NOMINAL DEGF
•
WASHER THICKNESS: 0.025 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
LUBRICATIONDRY FILM LUBRICANT
OVERALL HEIGHT0.235 INCHES MINIMUM AND 0.265 INCHES MAXIMUM IN
WASHER OUTSIDE DIAMETER0.325 INCHES MAXIMUM IN
WIDTH ACROSS FLATS0.243 INCHES MINIMUM AND 0.252 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD SERIESUNIFIED NATIONAL JOINT FINE (UNJF)
TEMP RATING450.0 FAHRENHEIT NOMINAL DEGF
WASHER THICKNESS0.025 INCHES NOMINAL IN
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 5525 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5737 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
THREAD DIRECTIONRIGHT-HAND
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
E12695-3Reference 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 ST3M787-3?
ST3M787-3 is a NUT,SELF-LOCKING,EXTENDED WASHER.
What parts can replace ST3M787-3?
There is 1 known substitute for ST3M787-3: E12695-3. Substitute compatibility should be verified for your specific system.
What is the NSN for ST3M787-3?
ST3M787-3 is cataloged in the U.S. Government catalog under NSN 5310-01-181-5045. 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.