Designation system

The designations of SKF super-precision bearings follow a system that consists of a basic designation with or without one or more prefixes and/or suffixes.
An example and the applicable options for double direction angular contact thrust ball bearings are given below.
Basic bearing designation system

Examples

BTW 70 CTN9/SPW33whereBTW 70 =
C =
TN9 =
SP =
W33 =
BTM 150 AM/HCP4CDBAwhereBTM 150 =
A =
M =
HC =
P4C =
DB =
A =

Applicable options for double direction angular contact thrust ball bearings

Test Designation 1
Prefixes (n.a.)

Test Designation 2
Basic Designation
BTWBasic design double direction angular contact thrust ball bearing
BTMHigh-speed design double direction angular contact thrust ball bearing
35
to
200
Bore diameter [mm]

Catalogue image - Test Designation 3
Suffixes - Internal design
A30° contact angle
B40° contact angle
C60° contact angle
AAs a second letter after the contact angle information (for BTW series only): Bearing with a larger bore to to be mounted on the large diameter side of a cylindrical roller bearing with a tapered bore.

Test Designation 4
Suffixes - External design (seals, snap ring groove etc.) (n.a.)

Catalogue image - Test Designation 5
Suffixes - Cage design
MTwo machined brass cages, snap-type (for BTW series), window-type (for BTM series), ball centred
TN9Two glass fibre reinforced PA66 cages, snap-type (for BTW series), window-type (for BTM series), ball centred

Catalogue image - Test Designation 6.1
Suffixes - Materials, heat treatment
Carbon chromium steel (no designation suffix)
HCBalls made of bearing grade silicon nitride Si3N4 (hybrid bearing)

Test Designation 6.2
Suffixes - Accuracy, clearance, preload, quiet running
P4CDimensional accuracy approximately to ISO tolerance class 4 and running accuracy better than ISO tolerance class 4 for radial bearings (for BTM series bearings only).
SPDimensional accuracy approximately to ISO tolerance class 5 and running accuracy better than ISO tolerance class 4 for thrust bearings (for BTW series bearings only).
UPDimensional accuracy approximately to ISO tolerance class 4 and running accuracy better than ISO tolerance class 4 for thrust bearings (for BTW series bearings only).

Catalogue image - Test Designation 6.3
Suffixes - Bearing sets, matched bearings (for BTM series bearing only)
Arrangement
DBTwo bearings arranged back-to-back
Preload
ALight preload
BHeavy preload
G...Special preload, expressed in daN e.g. G240

Test Designation 6.4
Suffixes - Stabilization (n.a.)


Suffixes - Lubrication
W33Annular groove and three lubrication holes in the housing washer (for BTW series bearing only)

Test Designation 6.6
Suffixes - Other variants (n.a.)
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