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.
Examples and the applicable options for cylindrical roller bearings are given below.
Examples
| Single row bearing | |||
| N 1016 KPHA/HC5SP | where | N 1016 = |  |
| K = |  |
||
| PHA = |  |
||
| HC5 = |  |
||
| SP = |  |
||
| Double row bearings | |||
| NN 3020 KTN9/SPVR521 | where | NN 3020 = | |
| K = | |
||
| TN9 = | |
||
| SP = | |
||
| VR521 = |  |
||
| NNU 49/500 B/SPC3W33X | where | NNU 49/500 = | |
| B = | |
||
| SP = | |
||
| C3 = | |
||
| W33X = |  |
||
 | Prefixes (n.a.) |
|
| Basic designation |
| Bearing design | |
| N | Single row cylindrical roller bearing |
| NN | Double row cylindrical roller bearing |
| NNU | Double row cylindrical roller bearing |
| Dimension series | |
| 10 | In accordance with ISO dimension series 10 |
| 30 | In accordance with ISO dimension series 30 |
| 49 | In accordance with ISO dimension series 49 |
| Bearing size | |
| 05
to 92 | (x5) 25 mm bore diameter
(x5) 460 mm bore diameter |
| from
/500 |
Bore diameter uncoded [mm] |
|
| Suffixes - Internal design and bore shape |
| – | Cylindrical bore (no designation suffix) |
| B | Modified internal design |
| K
| Tapered bore, taper 1:12 |
 | Suffixes - External design (seals, snap ring groove etc.) (n.a.) |
|
| Suffixes - Cage design |
| –
| Machined brass cage, roller centred (no designation suffix) |
| PHA | Carbon fibre reinforced PEEK cage, outer ring centred |
| TN
| PA66 cage, roller centred
|
| TN9
| Glass fibre reinforced PA66 cage, roller centred
|
| TNHA | Glass fibre reinforced PEEK cage, outer ring centred |
|
| Suffixes - Materials, heat treatment |
| – | Carbon chromium steel (no designation suffix) |
| HC5 | Rollers made of bearing grade silicon nitride Si3N4 (hybrid bearing) |
|
| Suffixes - Accuracy, clearance, preload, quiet running | |
| Accuracy | ||
| SP | Dimensional accuracy in accordance with ISO tolerance class 5, running accuracy in accordance with ISO tolerance class 4 | |
| UP | Dimensional accuracy in accordance with ISO tolerance class 4, running accuracy better than ISO tolerance class 4 | |
| Internal clearance
|
||
| – | Standard radial internal clearance C1 (no designation suffix) | |
| C2 | Radial internal clearance greater than C1 | |
| CN | Normal radial internal clearance | |
| C3 | Radial internal clearance greater than Normal | |
| Suffixes - Bearing sets, matched bearings (n.a.) |
 | Suffixes - Stabilization (n.a.) |
| Suffixes - Lubrication |
| W33 | Annular groove and three lubrication holes in the outer ring |
| W33X | Annular groove and six lubrication holes in the outer ring |
|
| Suffixes - Other variants |
| VR521 | Bearing supplied with measuring report (standard for NN 30 series bearings with d > 130 mm) |
| VU001 | Inner ring raceway with finish-grinding allowance |
