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78AX8 — BEARING,ROLLER,TAPERED

✓ Government record, cited
— · TAPERED BEARING
PRODUCT OVERVIEW

78AX8: BEARING,ROLLER,TAPERED.

The BEARING,ROLLER,TAPERED is a the manufacturer tape media or drive component used in enterprise backup, archival, and disaster recovery environments. Key specifications include material: STEEL OVERALL, cup_width: 0.8490 INCHES NOMINAL IN, cone_width: 2.3438 INCHES NOMINAL IN, bore_diameter: 3.1875 INCHES MINIMUM AND 3.1885 INCHES MAXIMUM IN, overall_width: 2.3750 INCHES MINIMUM AND 2.4350 INCHES MAXIMUM IN, alignment_type: RIGID. This part is cataloged in the U.S.

Government catalog under NSN 3110-00-774-4487, 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
78AX8
NSN: 3110-00-774-4487
FSC: 3110 — Bearings, Antifriction, Unmounted
CAGE: 76040 — MACK TRUCKS INC PARTS OPN (USA)
SPECIFICATIONS
materialSTEEL OVERALL
cup_width0.8490 INCHES NOMINAL IN
cone_width2.3438 INCHES NOMINAL IN
bore_diameter3.1875 INCHES MINIMUM AND 3.1885 INCHES MAXIMUM IN
overall_width2.3750 INCHES MINIMUM AND 2.4350 INCHES MAXIMUM IN
alignment_typeRIGID
style_designatorSTRAIGHT BORE, DOUBLE CONE, SINGLE CUP
cone_corner_radius0.0600 INCHES NOMINAL IN
backface_corner_radius0.1300 INCHES NOMINAL IN
overall_outside_diameter5.3750 INCHES MINIMUM AND 5.3760 INCHES MAXIMUM IN
retainer_fabrication_methodPRESSED
standard_tolerance_designationAFBMA CLASS 2
NSN3110-00-774-4487
COMPONENT DIAGRAM
TAPERED ROLLER BEARING — CUP & CONE ASSEMBLY CAGE CUP BORE CONE OD: — · BORE: — · WIDTH: — Single Row · PN: 78AX8 · OEM ⚠ VERIFY BEFORE ORDERING Cup and cone sold separately — verify you are ordering BOTH parts or the correct component. Always replace cup and cone together — mismatched wear = premature failure ✓ BROKER TIP Taper angle determines axial load capacity. Steeper angle = higher axial load rating. Timken series numbers indicate dimensions — cross-reference carefully PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
RETAINER FABRICATION METHOD: PRESSED
•
CUP WIDTH: 0.8490 INCHES NOMINAL IN
•
STYLE DESIGNATOR: STRAIGHT BORE, DOUBLE CONE, SINGLE CUP
•
OVERALL OUTSIDE DIAMETER: 5.3750 INCHES MINIMUM AND 5.3760 INCHES MAXIMUM IN
•
BACKFACE CORNER RADIUS: 0.1300 INCHES NOMINAL IN
•
CONE CORNER RADIUS: 0.0600 INCHES NOMINAL IN
•
ALIGNMENT TYPE: RIGID
TYPICAL APPLICATIONS
  • Long-term data archival and compliance retention
  • Offsite backup and disaster recovery
  • Air-gapped ransomware protection
  • Cold storage tier for infrequently accessed data
TECHNICAL CHARACTERISTICS
RETAINER FABRICATION METHODPRESSED
CUP WIDTH0.8490 INCHES NOMINAL IN
STYLE DESIGNATORSTRAIGHT BORE, DOUBLE CONE, SINGLE CUP
OVERALL WIDTH2.3750 INCHES MINIMUM AND 2.4350 INCHES MAXIMUM IN
OVERALL OUTSIDE DIAMETER5.3750 INCHES MINIMUM AND 5.3760 INCHES MAXIMUM IN
BACKFACE CORNER RADIUS0.1300 INCHES NOMINAL IN
CONE CORNER RADIUS0.0600 INCHES NOMINAL IN
ALIGNMENT TYPERIGID
CONE WIDTH2.3438 INCHES NOMINAL IN
STANDARD TOLERANCE DESIGNATIONAFBMA CLASS 2
SUBSTITUTES & CROSS-REFERENCES 1
496D-493-Y4S493Same 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 78AX8?
78AX8 is a BEARING,ROLLER,TAPERED.
What parts can replace 78AX8?
There is 1 known substitute for 78AX8: 496D-493-Y4S493. Substitute compatibility should be verified for your specific system.
What is the NSN for 78AX8?
78AX8 is cataloged in the U.S. Government catalog under NSN 3110-00-774-4487. 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.