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4W33551P4 — WASHER,FLAT

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

4W33551P4: WASHER,FLAT.

The WASHER,FLAT is a the manufacturer industrial component. Key specifications include thickness: 0.062 INCHES NOMINAL IN, hole_diameter: 0.562 INCHES NOMINAL IN, width_across_flats: 1.375 INCHES NOMINAL IN, peripheral_shape_style: SQUARE, center_hole_shape_style: ROUND, cross-sectional_shape_style: RECTANGULAR. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-481-0139, 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
4W33551P4
NSN: 5310-00-481-0139
FSC: 5310 — Nuts and Washers
CAGE: 75477 — FM AF, LLC DBA AMERICAN FAN COMPANY (USA)
SPECIFICATIONS
thickness0.062 INCHES NOMINAL IN
hole_diameter0.562 INCHES NOMINAL IN
width_across_flats1.375 INCHES NOMINAL IN
peripheral_shape_styleSQUARE
center_hole_shape_styleROUND
cross-sectional_shape_styleRECTANGULAR
NSN5310-00-481-0139
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 4W33551P4 · 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
•
WIDTH ACROSS FLATS: 1.375 INCHES NOMINAL IN
•
CROSS-SECTIONAL SHAPE STYLE: RECTANGULAR
•
PERIPHERAL SHAPE STYLE: SQUARE
•
CENTER HOLE SHAPE STYLE: ROUND
•
HOLE DIAMETER: 0.562 INCHES NOMINAL IN
•
THICKNESS: 0.062 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS1.375 INCHES NOMINAL IN
CROSS-SECTIONAL SHAPE STYLERECTANGULAR
PERIPHERAL SHAPE STYLESQUARE
CENTER HOLE SHAPE STYLEROUND
HOLE DIAMETER0.562 INCHES NOMINAL IN
THICKNESS0.062 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.
5310-00-000-0040 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
4W-33551-4Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
58E151040P39Reference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 4W33551P4?
4W33551P4 is a WASHER,FLAT.
What parts can replace 4W33551P4?
There are 2 known substitutes for 4W33551P4: 4W-33551-4, 58E151040P39. Substitute compatibility should be verified for your specific system.
What is the NSN for 4W33551P4?
4W33551P4 is cataloged in the U.S. Government catalog under NSN 5310-00-481-0139. 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.