PartsTable
Technical Data Sheet
PartsTable / COMPONENT / MS21231-5
MS21231-5 ✓ Verified by PartsTable
— · BALL BEARING
WHAT YOU NEED TO KNOW
2RS = sealed for life, ZZ = shielded re-greaseable ABEC grade: higher = tighter tolerance
ABEC-1 standard, ABEC-7+ for precision spindles
PRODUCT OVERVIEW

The BEARING,PLAIN,SELF-ALIGNING is a the manufacturer industrial component. Key specifications include material: STEEL COMP 440C INNER MEMBER, bore_diameter: 0.3120 INCHES MINIMUM AND 0.3125 INCHES MAXIMUM IN, style_designator: WITH INSERT AND/OR LINER, inner_member_width: 0.4350 INCHES MINIMUM AND 0.4370 INCHES MAXIMUM IN, outer_member_width: 0.3120 INCHES MINIMUM AND 0.3220 INCHES MAXIMUM IN, static_radial_load_rating: 9400 POUNDS LBS. This product is currently in active production with full OEM support.

This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 3120-00-079-9974, 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
MS21231-5
NSN: 3120-00-079-9974
FSC: 3120
CAGE: 96906 — MILITARY STANDARDS PROMULGATED BY MILITARY DEPARTMENTS UNDER AUTHORITY OF DEFENSE STANDARDIZATION MANUAL 4120 3-M
SPECIFICATIONS
materialSTEEL COMP 440C INNER MEMBER
bore_diameter0.3120 INCHES MINIMUM AND 0.3125 INCHES MAXIMUM IN
style_designatorWITH INSERT AND/OR LINER
inner_member_width0.4350 INCHES MINIMUM AND 0.4370 INCHES MAXIMUM IN
outer_member_width0.3120 INCHES MINIMUM AND 0.3220 INCHES MAXIMUM IN
static_radial_load_rating9400 POUNDS LBS
outer_member_outside_diameter0.6870 INCHES MINIMUM AND 0.6875 INCHES MAXIMUM IN
material_document_and_classificationAMS 5643 ASSN STD SINGLE MATERIAL RESPONSE OUTER RING
part_name_assigned_by_controlling_agencyBEARING, PLAIN, SELF LUBRICATGING, SELF-ALIGNING, LOW SPEED, WIDE, CHAMFERED, OUTER RING -65 DEGREES TO 325 DEGREES
NSN3120-00-079-9974
COMPONENT DIAGRAM
BALL BEARING — SEAL TYPE DETERMINES MAINTENANCE OD: — · BORE: — · WIDTH: — SEAL: Open · PN: MS21231-5 · 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
•
BORE DIAMETER: 0.3120 INCHES MINIMUM AND 0.3125 INCHES MAXIMUM IN
•
OUTER MEMBER OUTSIDE DIAMETER: 0.6870 INCHES MINIMUM AND 0.6875 INCHES MAXIMUM IN
•
HARDNESS RATING: 23.0 ROCKWELL C MINIMUM OUTER RACE MEMBER
•
MATERIAL: STEEL COMP 440C INNER MEMBER
•
STYLE DESIGNATOR: WITHOUT INSERT OR LINER
•
OUTER MEMBER WIDTH: 0.3120 INCHES MINIMUM AND 0.3220 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS (FLIS)
BORE DIAMETER0.3120 INCHES MINIMUM AND 0.3125 INCHES MAXIMUM IN
OUTER MEMBER OUTSIDE DIAMETER0.6870 INCHES MINIMUM AND 0.6875 INCHES MAXIMUM IN
HARDNESS RATING23.0 ROCKWELL C MINIMUM OUTER RACE MEMBER
MATERIALSTEEL COMP 440C INNER MEMBER
STYLE DESIGNATORWITHOUT INSERT OR LINER
HARDNESS RATING55.0 ROCKWELL C MINIMUM INNER MEMBER
MATERIALSTEEL OUTER RACE MEMBER
OUTER MEMBER WIDTH0.3120 INCHES MINIMUM AND 0.3220 INCHES MAXIMUM IN
INNER MEMBER WIDTH0.4350 INCHES MINIMUM AND 0.4370 INCHES MAXIMUM IN
STATIC RADIAL LOAD RATING9400 POUNDS LBS
VERIFIED SUBSTITUTES & CROSS-REFERENCES 6
3120PL0685683Interchangeable
interchangeable cross-reference
interchangeable
AS14102Interchangeable
interchangeable cross-reference
interchangeable
MS14102-5Interchangeable
interchangeable cross-reference
interchangeable
AS21230Interchangeable
interchangeable cross-reference
interchangeable
MS21230-16Interchangeable
interchangeable cross-reference
interchangeable
MILB8942Interchangeable
Same NIIN cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is MS21231-5?
MS21231-5 is a BEARING,PLAIN,SELF-ALIGNING.
What parts can replace MS21231-5?
There are 6 known substitutes for MS21231-5: 3120PL0685683, AS14102, MS14102-5 and 3 more. Substitute compatibility should be verified for your specific system.
What is the NSN for MS21231-5?
MS21231-5 is cataloged in the Federal Logistics Information System (FLIS) under NSN 3120-00-079-9974. This indicates validated use in U.S. government and defense supply chains.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026