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A1378 — GEAR ASSEMBLY,SPEED DECREASER

✓ Government record, cited
— · BALL BEARING
PRODUCT OVERVIEW

A1378: GEAR ASSEMBLY,SPEED DECREASER.

The GEAR ASSEMBLY,SPEED DECREASER is a the manufacturer industrial component. Key specifications include diameter: 0.328 INCHES NOMINAL IN, material: STEEL COMP 1012 BAND, barrel_style: STRAIGHT ROUND TYPE, corner_shape: SQUARE ALL CORNERS, flange_style: FLANGE, barrel_height: 0.155 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 3120-00-203-8673, 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
A1378
NSN: 3120-00-203-8673
NIINs: 002038673, 002466055, 006873063, 007372833, 011728461, 011900945, 016072806, 016072809, 016642257, 017158894
FSC: 3120 — Bearings, Plain, Unmounted
CAGE: 13730 — AMSCO INC (USA)
SPECIFICATIONS
diameter0.328 INCHES NOMINAL IN
materialSTEEL COMP 1012 BAND
barrel_styleSTRAIGHT ROUND TYPE
corner_shapeSQUARE ALL CORNERS
flange_styleFLANGE
barrel_height0.155 INCHES NOMINAL IN
hole_diameter0.0960 INCHES MINIMUM AND 0.1010 INCHES MAXIMUM FIRST IN
overall_width0.625 INCHES NOMINAL IN
overall_length0.9800 INCHES MINIMUM AND 0.9900 INCHES MAXIMUM IN
surface_finish30.0 MICROINCHES OVERALL
user_designatorMAN AND WOMAN
special_featuresFULL COLOR, WITH WHITE 67101, SCARLET 67111, AND ULTRAMARINE BLUE 67118
NSN3120-00-203-8673
COMPONENT DIAGRAM
BALL BEARING — SEAL TYPE DETERMINES MAINTENANCE OD: — · BORE: — · WIDTH: — SEAL: Open · PN: A1378 · OEM ⚠ VERIFY BEFORE ORDERING ABEC grade: higher = tighter tolerance = higher cost. ABEC-1 is standard, ABEC-7+ for precision spindles. Open, shielded (ZZ), and sealed (2RS) versions have different max RPM ratings ✓ BROKER TIP 2RS = sealed for life (no maintenance). ZZ = shielded, re-greaseable. Open = must lubricate on install. Common interchange: 6205-2RS = 6205-2RSR = 6205-DDU (same bearing, different suffix) PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
SURFACE FINISH: 30.0 MICROINCHES OVERALL
•
CORNER SHAPE: SQUARE ALL CORNERS
•
BODY OUTSIDE DIAMETER: 0.8110 INCHES MINIMUM AND 0.8115 INCHES MAXIMUM IN
•
STYLE DESIGNATOR: SOLID, PLAIN, NO OUTSIDE FLANGES
•
MATERIAL DOCUMENT AND CLASSIFICATION: SAE ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
BODY INSIDE DIAMETER: 0.7190 INCHES MINIMUM AND 0.7200 INCHES MAXIMUM IN
•
ANTIROTATION/LUBRICATION TYPE AND QUANTITY: 2 HOLE
TECHNICAL CHARACTERISTICS
SURFACE FINISH30.0 MICROINCHES OVERALL
CORNER SHAPESQUARE ALL CORNERS
BODY OUTSIDE DIAMETER0.8110 INCHES MINIMUM AND 0.8115 INCHES MAXIMUM IN
STYLE DESIGNATORSOLID, PLAIN, NO OUTSIDE FLANGES
MATERIAL DOCUMENT AND CLASSIFICATIONSAE ASSN STD SINGLE MATERIAL RESPONSE OVERALL
OVERALL LENGTH0.9800 INCHES MINIMUM AND 0.9900 INCHES MAXIMUM IN
BODY INSIDE DIAMETER0.7190 INCHES MINIMUM AND 0.7200 INCHES MAXIMUM IN
ANTIROTATION/LUBRICATION TYPE AND QUANTITY2 HOLE
MATERIALCOPPER ALLOY 932 OVERALL
HOLE DIAMETER0.0960 INCHES MINIMUM AND 0.1010 INCHES MAXIMUM FIRST IN
SUBSTITUTES & CROSS-REFERENCES 2
625145Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
2810L19-011Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is A1378?
A1378 is a GEAR ASSEMBLY,SPEED DECREASER.
What parts can replace A1378?
There are 2 known substitutes for A1378: 625145, 2810L19-011. Substitute compatibility should be verified for your specific system.
What is the NSN for A1378?
A1378 is cataloged in the U.S. Government catalog under NSN 3120-00-203-8673. 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.