23938-CCK-W33 bearing: complete specifications & equivalents
The 23938-CCK-W33 is a ISO 15 radial bearing sized 190 x 260 x 52 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 190 mm |
| Outer diameter D | 260 mm |
| Width B | 52 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 499 kN |
| Basic static load rating C0 | 800 kN |
| Fatigue load limit Pu | 76.5 kN |
| Reference speed (thermal) | 2400 rpm |
| Limiting speed (mechanical) | 2600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 14500 g |
| Manufacturer designation | SKF 23938 CCK/W33 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.2 adapter-sleeve executions |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.2 adapter-sleeve executions) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.2 adapter-sleeve executions); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & 23900-series range
| Bore d | 7.48 in |
|---|---|
| Outer diameter D | 10.236 in |
| Width B | 2.047 in |
| ISO bore code | 38 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 23900-series | 180 mm |
| Largest outer diameter in 23900-series | 650 mm |
| Width range across 23900-series | 52–128 mm |
| Bore position in 23900-series (smallest first) | 2 of 17 |
| Bore above smallest 23900-series size | 10 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23938 | SKF | full Dimensions and internal design equivalent — standard interchange. | Tapered-bore (1:12) sleeve-mounted execution of 23938; identical ISO 15 envelope, fits H3938 adapter sleeve on a 170 mm shaft. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 23938-CCK-W33 model number is decoded
Ordering number SKF 23938 CCK/W33 in SKF catalogue PUB BU/P1 17000 is a double-row spherical roller bearing with a tapered bore (1:12), intended for an H-series adapter sleeve or AH withdrawal sleeve, with two pressed-steel cages with a floating guide ring and the same 190×260×52 mm ISO 15 outline as its cylindrical-bore counterpart. On the SKF nameplate, 23938-cck-w33 follows the ISO 15 convention: 2 for the spherical roller type, 39 for the dimension series 39 (compact OD, narrow), final digits 38 for the 190 mm bore. Note that K means 1:12 taper; the rarer K30 suffix means 1:30. Adapter sleeves (H) and withdrawal sleeves (AH) are ordered separately by shaft diameter, and the KM locknut plus MB lock washer used for drive-up are also separate components. The 76.5 kN Pu figure feeds the adjusted-life equation at contaminated or partial-film conditions, and the 1.60 C0/C balance shows this execution is tuned to heavy radial-plus-axial duty with misalignment tolerance. Mounting on the 1:12 taper is controlled by clearance reduction or measured axial drive-up, never by locknut torque: SKF tables give the target radial-clearance decrease for the 190 mm 23938-cck-w33, checked with feeler gauges before and after drive-up.
Typical equipment & failure modes
Common applications
- steel-plant continuous-caster segments
- large induced-draft fan rotors
- heavy crusher and screen shafts mounted and dismounted with hydraulic nuts
- long through-shafts in conveyors, where a sleeve seat avoids a precision journal
Known failure patterns
- raceway fatigue spalling of the sphered outer raceway after extended service above the catalogue L10 rating
- inner-ring raceway spalling from edge loading when misalignment exceeds the self-aligning recovery range
- inner-ring circumferential cracking after over-drive on the tapered seat removes too much radial clearance and the bearing runs preloaded
- surface distress and smearing when the relubrication interval is exceeded — the W33 groove is only effective if grease actually reaches the roller rows
- electrical pitting on VFD-driven shafts without grounding protection
Selection pitfalls — read before you substitute
- At 190 mm bore the ring mass makes cocking during mounting a real risk; guide the bearing square, confirm seat contact around the full circumference, and re-check the self-aligning swing after the housing cap is torqued down.
- The 23900-series series at 190 mm bore (260×52 mm) is the slim-OD envelope: it buys radial space but gives up capacity against a 222-series bearing of the same bore — confirm the L10 margin before downsizing into it.
- The 23938-cck-w33 and its cylindrical-bore counterpart 23938-cc-w33 share envelope and load ratings (499/800 kN) but are not interchangeable in a housing already fitted for direct shaft mounting — the sleeve changes the assembly stack-up.
- The 23938-cck-w33 and its cylindrical-bore counterpart 23938-cc-w33 share envelope and load ratings (499/800 kN) but are not interchangeable in a housing already fitted for direct shaft mounting — the sleeve changes the assembly stack-up.
- Catalogue reference speed and limiting speed are different limits: the 2,400 r/min reference is a thermal criterion under load, while the 2,600 r/min limiting value is the mechanical ceiling — observe both.
- The 499/800 kN ratings are SKF catalogue values for this tapered-bore execution (SKF 23938 CCK/W33); sleeve, KM nut and MB washer are separate order numbers, and the catalogue version (SKF catalogue PUB BU/P1 17000) should travel with the mounting specification.
Frequently asked questions
What are the dimensions and catalogue data of 23938-cck-w33?
The SKF 23938 CCK/W33 is a double-row spherical roller bearing with a 1:12 tapered bore, 190 mm nominal bore, 260 mm outer diameter and 52 mm width (7.48 × 10.236 × 2.047 in) per ISO 15. From SKF catalogue PUB BU/P1 17000: C 499 kN, C0 800 kN, Pu 76.5 kN, reference speed 2,400 r/min, limiting speed 2,600 r/min, mass about 14500 g. It is mounted on an adapter (H) or withdrawal (AH) sleeve, not directly on the shaft.
What does the K suffix mean on 23938-cck-w33?
K marks a 1:12 tapered bore for sleeve mounting — SKF writes EK or CCK(/W33), FAG writes -K- inside the suffix chain for sleeve mounting. The bearing seats on an H-series adapter sleeve with a KM locknut and MB lock washer (plain shaft, h9 tolerance), or on an AH withdrawal sleeve against a shaft shoulder. The rarer K30 suffix would instead mean a 1:30 taper; dimension series 40/41 spherical rollers commonly use it.
Which adapter sleeve fits the 23938-cck-w33?
The sleeve is selected by the actual shaft diameter in millimetres, not only by the 190 mm nominal bore: SKF H-sleeve numbers each cover a small shaft-diameter range and are width-series specific (H39/H30/H31/H32 matching dimension series 39/40/31/32), and each kit bundles the sleeve, KM locknut and MB lock washer. For shoulder locations use an AH withdrawal sleeve instead. Confirm the sleeve number against the SKF catalogue PUB BU/P1 17000 mounting tables for your shaft size.
How is the 23938-cck-w33 driven up and checked?
Mounting is controlled by radial-clearance reduction or axial drive-up distance from the SKF catalogue tables for the 1:12 taper, never by locknut torque. Measure clearance with feeler gauges before and after tightening the KM nut, stop at the tabulated decrease, and lock the MB washer tab. Over-drive removes too much clearance (inner-ring cracking risk); under-drive lets the sleeve creep and fret.
What is the difference between 23938-cck-w33 and 23938-cc-w33?
They share the ISO 15 envelope and the same 499/800 kN ratings, but 23938-cck-w33 has the 1:12 tapered bore for sleeve mounting on a plain shaft, while 23938-cc-w33 has a cylindrical bore for direct mounting on a machined interference journal (typically m6 with H7 housing). They are separate order numbers, not interchangeable in the same shaft arrangement.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.2 adapter-sleeve executions on 2026-09-26. Read our editorial & correction policy.