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550-040 — 550-040

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

550-040: 550-040.

The 550-040 is a the manufacturer industrial component. Key specifications include nut_style: HEXAGON, nut_height: 0.230 INCHES MINIMUM AND 0.250 INCHES MAXIMUM IN, special_features: UNDERWATER LIFE SUPPORT IAW NAVSEA INSTRUCTION 10560.2B, width_across_flats: 0.750 INCHES NOMINAL IN, end_item_identification: MK21MOD1 DIVING HELMET-SUPERLITE-AIR/MIXED, criticality_code_justification: FEAT. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-204-6602, 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
550-040
NSN: 5310-01-204-6602
NIINs: 012046602, 013474305
FSC: 5310 — Nuts and Washers
CAGE: 58366 — KIRBY MORGAN DIVE SYSTEMS INC (USA)
SPECIFICATIONS
nut_styleHEXAGON
nut_height0.230 INCHES MINIMUM AND 0.250 INCHES MAXIMUM IN
special_featuresUNDERWATER LIFE SUPPORT IAW NAVSEA INSTRUCTION 10560.2B
width_across_flats0.750 INCHES NOMINAL IN
end_item_identificationMK21MOD1 DIVING HELMET-SUPERLITE-AIR/MIXED
criticality_code_justificationFEAT
NSN5310-01-204-6602
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 550-040 · 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
SUBSTITUTES & CROSS-REFERENCES 1
DE087Same 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 550-040?
550-040 is a 550-040.
What parts can replace 550-040?
There is 1 known substitute for 550-040: DE087. Substitute compatibility should be verified for your specific system.
What is the NSN for 550-040?
550-040 is cataloged in the U.S. Government catalog under NSN 5310-01-204-6602. 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.