23280-CAK-W33 bearing: complete specifications & equivalents
The 23280-CAK-W33 is a ISO 15 radial bearing sized 400 x 720 x 256 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 400 mm |
| Outer diameter D | 720 mm |
| Width B | 256 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass, machined (M1) |
| Basic dynamic load rating C | 6881 kN |
| Basic static load rating C0 | 10400 kN |
| Fatigue load limit Pu | 680 kN |
| Reference speed (thermal) | 480 rpm |
| Limiting speed (mechanical) | 670 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 505000 g |
| Manufacturer designation | SKF 23280 CAK/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 & 23200-series range
| Bore d | 15.748 in |
|---|---|
| Outer diameter D | 28.346 in |
| Width B | 10.079 in |
| ISO bore code | 80 |
| Radial section height (D−d)/2 | 160 mm |
| Smallest bore in 23200-series | 90 mm |
| Largest outer diameter in 23200-series | 870 mm |
| Width range across 23200-series | 52.4–310 mm |
| Bore position in 23200-series (smallest first) | 22 of 26 |
| Bore above smallest 23200-series size | 310 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23280 | SKF | full Dimensions and internal design equivalent — standard interchange. | Tapered-bore (1:12) sleeve-mounted execution of 23280; identical ISO 15 envelope, fits OH3280 adapter sleeve on a 380 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 23280-CAK-W33 model number is decoded
Ordering number SKF 23280 CAK/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 a one-piece machined brass cage guided on the inner ring (CA design) and the same 400×720×256 mm ISO 15 outline as its cylindrical-bore counterpart. Reading the designation: the leading 2 marks a spherical roller bearing, the 32 is the ISO 15 dimension series (dimension series 32 (medium OD, extra wide)), and the last two digits encode the 400 mm bore; the 720 mm OD and 256 mm width follow the ISO 15 general plan. Reading the suffix on 23280-cak-w33, the K (or EK/CCK) element changes only the bore — 1:12 taper for sleeve mounting — while the rest of the suffix chain (CA machined-brass-cage design with W33 groove) keeps the same internal design, cage and W33 relubrication features as the cylindrical-bore 23280-cak-w33. The 160.0 mm radial section height ((720−400)/2) and 505000 g catalogue mass frame a 400 mm bore bearing rated at 6881 kN C — roughly 17.20 kN of dynamic capacity per millimetre of bore before application factors. At 400 mm bore, dismount after service is by KM locknut reversal or a hydraulic nut on larger sizes; oil-injection grooves on the bigger sleeves let pressurised oil float the 23280-cak-w33 off the taper without scoring either surface.
Typical equipment & failure modes
Common applications
- wind-turbine main shaft support
- heavy rolling-mill work-roll chocks
- shafting produced to commercial tolerances, where the adapter sleeve supplies the precision seat
- split-housing plummer block arrangements with bearings swapped in situ
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
- smearing on the roller-raceway contact during skid starts below the minimum load
Selection pitfalls — read before you substitute
- At 400 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 23200-series series at 400 mm bore (720×256 mm) adds still more width for shock-loaded and vibratory loads; it does not interchange with a 231 bearing of the same bore because the 256 mm width changes abutment spacing, even though the 720 mm OD matches.
- A loose sleeve after the first weeks of service usually means inadequate initial drive-up; re-checking clearance without dismounting is possible through the 256 mm-wide roller rows with feeler gauges — do not simply tighten the KM nut until vibration stops.
- The 23280-cak-w33 and its cylindrical-bore counterpart 23280-cak-w33 share envelope and load ratings (6881/10400 kN) but are not interchangeable in a housing already fitted for direct shaft mounting — the sleeve changes the assembly stack-up.
- Never use the tapered-bore EK/K variant's drive-up figures on this cylindrical-bore 23280-cak-w33; clearance reduction targets differ, and over-driving a cylindrical bore onto an oversized journal cracks the inner ring.
- The 6881/10400 kN ratings are SKF catalogue values for this tapered-bore execution (SKF 23280 CAK/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 23280-cak-w33?
The SKF 23280 CAK/W33 is a double-row spherical roller bearing with a 1:12 tapered bore, 400 mm nominal bore, 720 mm outer diameter and 256 mm width (15.748 × 28.346 × 10.079 in) per ISO 15. From SKF catalogue PUB BU/P1 17000: C 6881 kN, C0 10400 kN, Pu 680 kN, reference speed 480 r/min, limiting speed 670 r/min, mass about 505000 g. It is mounted on an adapter (H) or withdrawal (AH) sleeve, not directly on the shaft.
What does the K suffix mean on 23280-cak-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 23280-cak-w33?
The sleeve is selected by the actual shaft diameter in millimetres, not only by the 400 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 23280-cak-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 23280-cak-w33 and 23280-cak-w33?
They share the ISO 15 envelope and the same 6881/10400 kN ratings, but 23280-cak-w33 has the 1:12 tapered bore for sleeve mounting on a plain shaft, while 23280-cak-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.