Designation system

The designations of most SKF rolling bearings follow a system that may consist of a basic designation with or without one or more prefixes and/or suffixes (→ Basic bearing designation system).

An example and the applicable options for four-point contact ball bearings are given below.

Example

QJ 318 N2PHAS	where	QJ 318 =
		N2 =
		PHAS =

Prefixes (n.a.)

	Basic designation
Listed in table 1

Suffixes - Internal design (n.a.)

	Suffixes - External design (seals, snap ring groove etc.)
N2	Two locating slots (notches) in one outer ring side face, 180° apart

	Suffixes - Cage design
FA	Machined steel cage, outer ring centred
MA	Machined brass cage, outer ring centred.
PHAS	Glass fibre reinforced PEEK cage, with lubrication grooves in the guiding surface, outer ring centred

Suffixes - Materials, heat treatment (n.a.)

	Suffixes - Accuracy, clearance, preload, quiet running
B20	Reduced width tolerance
P6	Dimensional and geometrical tolerances to class P6
P62	P6 + C2
P63	P6 + C3
P64	P6 + C4
P6CNL	P6 + CNL
CNL	Axial internal clearance in the lower half of the Normal range
C2	Axial internal clearance smaller than Normal
C2H	Axial internal clearance in the upper half of the C2 range
C2L	Axial internal clearance in the lower half of the C2 range
C3	Axial internal clearance greater than Normal
C4	Axial internal clearance greater than C3
344524	C2H + CNL