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51631B — 51631B

✓ Government record, cited
— · MRO · MRO_GENERAL
PRODUCT OVERVIEW

51631B: 51631B.

The 51631B is a the manufacturer industrial component. Key specifications include corner_shape: SQUARE ALL CORNERS, overall_length: 2.2500 INCHES NOMINAL IN, style_designator: SOLID, PLAIN, NO OUTSIDE FLANGES, body_inside_diameter: 2.2560 INCHES MINIMUM AND 2.2570 INCHES MAXIMUM IN, body_outside_diameter: 2.7520 INCHES MINIMUM AND 2.7530 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 3120-00-661-7785, 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
MRO→ MRO_GENERAL→ 51631B
NSN: 3120-00-661-7785
NIINs: 006617785, 013381738
FSC: 3120 — Bearings, Plain, Unmounted
CAGE: 50024 — COLTEC INDUSTRIES INC DBA FAIRBANKS MORSE ENGINE FM/ALCO (USA)
SPECIFICATIONS
materialCOPPER ALLOY 934 OR COPPER ALLOY 910 OR COPPER ALLOY 932 OR COPPER ALLOY 938 OR COPPER ALLOY 940 OR COPPER ALLOY 943 OUTER LAYER
corner_shapeSQUARE ALL CORNERS
overall_length2.2500 INCHES NOMINAL IN
style_designatorSOLID, PLAIN, NO OUTSIDE FLANGES
body_inside_diameter2.2560 INCHES MINIMUM AND 2.2570 INCHES MAXIMUM IN
body_outside_diameter2.7520 INCHES MINIMUM AND 2.7530 INCHES MAXIMUM IN
NSN3120-00-661-7785
COMPONENT DIAGRAM
BALL BEARING — SEAL TYPE DETERMINES MAINTENANCE OD: — · BORE: — · WIDTH: — SEAL: Open · PN: 51631B · 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
•
CORNER SHAPE: SQUARE ALL CORNERS
•
BODY OUTSIDE DIAMETER: 2.7520 INCHES MINIMUM AND 2.7530 INCHES MAXIMUM IN
•
STYLE DESIGNATOR: SOLID, PLAIN, NO OUTSIDE FLANGES
•
BODY INSIDE DIAMETER: 2.2560 INCHES MINIMUM AND 2.2570 INCHES MAXIMUM IN
•
MATERIAL: COPPER ALLOY 934 OR COPPER ALLOY 910 OR COPPER ALLOY 932 OR COPPER ALLOY 938 OR COPPER ALLOY 940 OR COPPER ALLOY 943 OUTER LAYER
TECHNICAL CHARACTERISTICS
CORNER SHAPESQUARE ALL CORNERS
BODY OUTSIDE DIAMETER2.7520 INCHES MINIMUM AND 2.7530 INCHES MAXIMUM IN
STYLE DESIGNATORSOLID, PLAIN, NO OUTSIDE FLANGES
OVERALL LENGTH2.2500 INCHES NOMINAL IN
BODY INSIDE DIAMETER2.2560 INCHES MINIMUM AND 2.2570 INCHES MAXIMUM IN
MATERIALCOPPER ALLOY 934 OR COPPER ALLOY 910 OR COPPER ALLOY 932 OR COPPER ALLOY 938 OR COPPER ALLOY 940 OR COPPER ALLOY 943 OUTER LAYER
SUBSTITUTES & CROSS-REFERENCES 4
16N825PC25Reference document
Same NSN cross-reference
Reference document — Secondary reference
16N950PC25Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
16N970PC25Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
16D46716-2Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
LIFECYCLE
NSN statusCancelled· U.S. Government catalog
Acquisition advice: Terminal item — stock exhausted; no further procurementNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 51631B?
51631B is a 51631B. It is classified as a MRO (MRO_GENERAL).
What parts can replace 51631B?
There are 4 known substitutes for 51631B: 16N825PC25, 16N950PC25, 16N970PC25 and 1 more. Substitute compatibility should be verified for your specific system.
What is the NSN for 51631B?
51631B is cataloged in the U.S. Government catalog under NSN 3120-00-661-7785. 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.