ball and roller bearings - NTN Bearing Corporation of

1. PREFIX
ET: NTN Endurance tapered roller bearings, case hardened material
4T: NTN 4-Top tapered roller bearings, case hardened material
E: Case hardened steel
T: Internationally interchangeable dimensions
2. SERIES
H: Heavy
HH: Heavier than heavy
HM: Heavy-medium
L: Light
LM: Light medium
M: Medium
ISO: Metric series 320X, 302, 322, 303 and 323
Inch Series
ISO Series
TAPERED
ROLLER
BEARING
NUMBERING
SYSTEM
3. SUFFIX
A: Different bore, O.D., width or radius from basic part number
PK: Class K for J-Line
PXn: Special tolerance, n; from 1 onward
S: Different bore, OD, width or radius from basic part number
U: ISO series; internationally interchangeable through hardened
steel
W: Slot or keyway
X: Different bore, O.D., width or radius from basic part number
-0: AFBMA class 0
-00: AFBMA class 00
-2: AFBMA class 2
-3: AFBMA class 3
-4: AFBMA class 4
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