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8M178 — COVER,ACCESS

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

8M178: COVER,ACCESS.

The COVER,ACCESS is a the manufacturer industrial component. Key specifications include material: STEEL, body_thickness: 0.047 INCHES NOMINAL IN, inside_diameter: 2.266 INCHES NOMINAL IN, flange_thickness: 0.047 INCHES NOMINAL IN, outside_diameter: 3.375 INCHES NOMINAL IN, surface_treatment: ENAMEL. This part is cataloged in the U.S.

Government catalog under NSN 5340-00-057-3090, 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
8M178
NSN: 5340-00-057-3090
FSC: 5340 — Hardware, Commercial
CAGE: 11083 — CATERPILLAR INC DIV CATERPILLAR DEFENSE (USA)
SPECIFICATIONS
materialSTEEL
body_thickness0.047 INCHES NOMINAL IN
inside_diameter2.266 INCHES NOMINAL IN
flange_thickness0.047 INCHES NOMINAL IN
outside_diameter3.375 INCHES NOMINAL IN
surface_treatmentENAMEL
body_outside_radius0.094 INCHES NOMINAL IN
inside_corner_radius0.094 INCHES NOMINAL IN
securing_device_typeTHREADED FASTENER
first_recess_diameter3.297 INCHES NOMINAL IN
outside_corner_radius0.094 INCHES NOMINAL IN
peripheral_shape_styleROUND, ONE HOLE
NSN5340-00-057-3090
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: 8M178 MFR: OEM ⚠ VERIFY BEFORE ORDERING Wrong material = failure. Viton for oil/fuel, EPDM for water/steam, Buna-N for general purpose, Silicone for food-grade. Chemical incompatibility causes swelling, brittleness, or rapid degradation ✓ BROKER TIP Durometer (hardness) affects sealing pressure tolerance. Higher Shore A = harder = higher pressure. Standard durometer is 70A — verify if application requires different hardness PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
FLANGE THICKNESS: 0.047 INCHES NOMINAL IN
•
INSIDE CORNER RADIUS: 0.094 INCHES NOMINAL IN
•
FIRST RECESS INSIDE HEIGHT: 0.188 INCHES NOMINAL IN
•
FIRST RECESS DIAMETER: 3.297 INCHES NOMINAL IN
•
SECOND RECESS INSIDE HEIGHT: 0.500 INCHES NOMINAL IN
•
MOUNTING OPENING SHAPE STYLE: THREADED HOLE
•
CROSS-SECTIONAL SHAPE STYLE: CIRCULAR RECESS
•
OUTSIDE DIAMETER: 3.375 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
FLANGE THICKNESS0.047 INCHES NOMINAL IN
INSIDE CORNER RADIUS0.094 INCHES NOMINAL IN
FIRST RECESS INSIDE HEIGHT0.188 INCHES NOMINAL IN
FIRST RECESS DIAMETER3.297 INCHES NOMINAL IN
SECOND RECESS INSIDE HEIGHT0.500 INCHES NOMINAL IN
MOUNTING OPENING SHAPE STYLETHREADED HOLE
CROSS-SECTIONAL SHAPE STYLECIRCULAR RECESS
OUTSIDE DIAMETER3.375 INCHES NOMINAL IN
BOLT HOLE CENTERLINE TO NEAREST EDGE DISTANCE1.687 INCHES NOMINAL IN
SECURING DEVICE TYPETHREADED FASTENER
SUBSTITUTES & CROSS-REFERENCES 1
P18739Reference document
Same NSN cross-reference
Reference document — Secondary reference
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 8M178?
8M178 is a COVER,ACCESS.
What parts can replace 8M178?
There is 1 known substitute for 8M178: P18739. Substitute compatibility should be verified for your specific system.
What is the NSN for 8M178?
8M178 is cataloged in the U.S. Government catalog under NSN 5340-00-057-3090. 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.