C3984-M bearing: complete specifications & equivalents
The C3984-M is a ISO 15 radial bearing sized 420 x 560 x 106 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 420 mm |
| Outer diameter D | 560 mm |
| Width B | 106 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 2160 kN |
| Basic static load rating C0 | 4250 kN |
| Fatigue load limit Pu | 310 kN |
| Reference speed (thermal) | 850 rpm |
| Limiting speed (mechanical) | 1200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 72000 g |
| Manufacturer designation | C 3984 M |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings); 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 & C3900-series range
| Bore d | 16.535 in |
|---|---|
| Outer diameter D | 22.047 in |
| Width B | 4.173 in |
| ISO bore code | 84 |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in C3900-series | 360 mm |
| Largest outer diameter in C3900-series | 2180 mm |
| Width range across C3900-series | 90–355 mm |
| Bore position in C3900-series (smallest first) | 3 of 15 |
| Bore above smallest C3900-series size | 60 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C3984-KM | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 420×560×106 mm ISO 15 envelope and equivalent catalogue C/C0; C 3984 KM is the 1:12 tapered-bore K M brass-caged execution of this size — boundary dimensions interchangeable, only mounting and cage execution differ. |
| 23984 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (420×560×106 mm) SKF spherical roller bearing SKF 23984 CC/W33 with ratings within 10 % — not a drop-in substitute: SKF 23984 CC/W33 locates the shaft axially while the CARB bearing must float; the two are designed to run as a locating/non-locating pair. |
| 23984-CCK-W33 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (420×560×106 mm) SKF spherical roller bearing SKF 23984 CCK/W33 with ratings within 10 % — not a drop-in substitute: SKF 23984 CCK/W33 locates the shaft axially while the CARB bearing must float; the two are designed to run as a locating/non-locating pair. |
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 C3984-M model number is decoded
C 3984 M is a CARB toroidal roller bearing to ISO 15: a single row of long, symmetrical barrel-shaped rollers between guide flanges, sized 420×560×106 mm, as listed in SKF catalogue PUB BU/P1 17000 ch. 10.1. In C 3984 M the 39 dimension series fixes the 560 mm OD and 106 mm width around the 420 mm bore (code 84 × 5); the suffix M then selects the cylindrical bore for direct shaft fitting, machined brass M cage. The open execution relies on the housing seals and lubrication system, fed through groove/hole features on the large sizes. Explorer-class heat treatment and the crowned roller profile keep edge stress down when the 420 mm shaft deflects; the 850 r/min reference and 1,200 r/min limiting speed are both catalogue values. Pairing rule: use the CARB bearing opposite one locating spherical or tapered bearing — never at both shaft ends — and check the locating bearing takes 100 % of the thrust, since C 3984 M deliberately carries none. After fitting, confirm the inner ring can be pushed axially by hand through the catalogue displacement range; a ring that will not slide means the position is locked and will preload in service.
Typical equipment & failure modes
Common applications
- continuous-caster guide rolls and slab-caster segments under heat growth
- vibrating screen exciters fitted with the VE240 tolerance execution
- long fan and kiln main shafts where the free end must float without thrust load
- heavy industrial gearbox layshafts used as the non-locating position
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after sustained overload
- edge loading and premature spalling when the CARB position is blocked from its designed axial float
- brass cage pocket wear under marginal lubrication in the large-bore M/MB executions
- condensation pitting in machines that run intermittently in humid environments
- grease churning and overheating when a high-speed thrust position is over-packed
Selection pitfalls — read before you substitute
- Above 200 mm bore these bearings weigh tens of kilograms (72 kg here) — lifting gear and induction heating are mandatory, and a cocked ring scores the toroidal raceway before start-up.
- Do not block the axial displacement in the drawing: housing covers, labyrinth rings and snap rings must leave the catalogue float (s) free, or the bearing silently becomes a poorly located fixed bearing.
- Envelope-identical spherical roller bearings (same ISO 15 d×D×B) are not drop-in equivalents — they locate the shaft axially, while C 3984 M must float; the two are designed to be used as a pair.
- Never use C 3984 M as the locating bearing: it carries no axial load by design — the arrangement needs a separate locating spherical, tapered or angular bearing facing the thrust.
- Tapered-bore K executions mount on adapter sleeves (1:12) and K30 on withdrawal sleeves (1:30) — the 420 mm bore changes the sleeve family, and the drive-up procedure differs accordingly.
- The 2160/4250 kN ratings and 72000 g mass are SKF catalogue values transcribed from ch. 10.1 of PUB BU/P1 17000 (PDF table page 866); mounting data — axial displacement (s) and seating details — appears in the running text because the structured record carries the boundary envelope only.
Frequently asked questions
How is C 3984 M mounted?
Slide or heat (max 120 °C) the bearing onto the 420 mm seat, give the outer ring a loose housing fit, leave the float travel unobstructed, and never press through the 106 mm roller set.
What are the dimensions and ratings of the C 3984 M?
A C 3984 M measures 420 mm bore × 560 mm outside diameter × 106 mm width (16.535 × 22.047 × 4.173 in). From SKF catalogue PUB BU/P1 17000: dynamic C 2160 kN, static C0 4250 kN, fatigue limit Pu 310 kN, reference speed 850 r/min, limiting speed 1,200 r/min, mass about 72000 g.
Can a CARB bearing like C 3984 M locate the shaft axially?
No — that is the defining feature. C 3984 M deliberately allows the inner ring to float axially inside the outer ring while the toroidal rollers self-align. It must be paired with a separate locating bearing (spherical, tapered or angular contact) that takes 100 % of the thrust.
How is the C 3984 M designation read?
C = CARB toroidal family; 39 = dimension series; 84 = 420 mm bore (code 84 × 5); suffix M selects cylindrical bore for direct shaft fitting, machined brass M cage. K is a 1:12 tapered bore for an adapter sleeve, K30 a 1:30 bore for a withdrawal sleeve.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings on 2026-09-27. Read our editorial & correction policy.