1220-K bearing: complete specifications & equivalents
The 1220-K is a ISO 15 radial bearing sized 100 x 180 x 34 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 100 mm |
| Outer diameter D | 180 mm |
| Width B | 34 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 68.9 kN |
| Basic static load rating C0 | 30 kN |
| Fatigue load limit Pu | 1.29 kN |
| Reference speed (thermal) | 7500 rpm |
| Limiting speed (mechanical) | 4800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3700 g |
| Manufacturer designation | 1220 K |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); 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 & 1200-series range
| Bore d | 3.937 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 1.339 in |
| ISO bore code | 20 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in 1200-series | 6 mm |
| Largest outer diameter in 1200-series | 230 mm |
| Width range across 1200-series | 6–154 mm |
| Bore position in 1200-series (smallest first) | 27 of 32 |
| Bore above smallest 1200-series size | 94 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 1220 | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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 1220-K model number is decoded
The 12xx series is the light/normal-section self-aligning ball bearing (ISO dimension series 02). the last two digits encode the bore: 1220 carries code 20 = 100 mm (code × 5). Envelope 100×180×34 mm (3.937×7.087×1.339 in) with a 40.0 mm radial section height, C 68.9 kN, C0 30 kN and Pu 1.29 kN. The open 1220 K carries no shields or seals and relies on application lubrication and external sealing. The suffix identifies the glass-fibre-reinforced polyamide 66 cage execution. The K suffix marks a 1:12 tapered bore for direct mounting on a tapered shaft or with an adapter sleeve. Reference (thermal) speed 7500 r/min, limiting speed 4800 r/min, catalogue mass 3700 g.
Typical equipment & failure modes
Common applications
- material-handling equipment
- industrial electric motors
- conveyor drum and pulley shafts
- agricultural gearboxes
Known failure patterns
- contamination wear when the open arrangement is used without adequate external sealing
- lubricant starvation where no regreasing interval is maintained
- adapter-sleeve fretting when the sleeve is not locked against the shaft shoulder
- incorrect sleeve tightening that leaves the tapered bore loose or over-expanded, changing internal clearance
- raceway smearing under marginal lubrication at start-up
- electrical pitting in VFD-driven motors without shaft grounding
Selection pitfalls — read before you substitute
- Catalogue ratings for 1220-K (C 68.9 kN, C0 30 kN) are SKF figures from PUB BU/P1 17000; geometry revisions can change ratings without changing the designation, so keep the catalogue edition with the specification.
- Catalogue ratings for 1220-K (C 68.9 kN, C0 30 kN) are SKF figures from PUB BU/P1 17000; geometry revisions can change ratings without changing the designation, so keep the catalogue edition with the specification.
- On a sleeve-mounted 1220-K, lock the sleeve against the shaft shoulder; a loose sleeve creeps and frets both the shaft and the bore.
- The suffix on 1220-K denotes a glass-fibre-reinforced polyamide 66 cage: quiet and light at the 4800 r/min limiting speed, but it softens above roughly 120 °C — check the oil temperature in hot drives.
- The spherical outer raceway lets 1220-K tolerate shaft deflection, but it does not increase thrust capacity — combined loads still need an angular-contact or deep-groove bearing.
- Fillet radii must clear the 1220-K chamfer so the 34 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
Frequently asked questions
What are the dimensions of 1220-K?
SKF 1220 K measures 100 mm bore × 180 mm OD × 34 mm width (3.937 × 7.087 × 1.339 in), mass about 3700 g. It is open, with no shields or seals.
How does the bore code in 1220 work?
The final two digits of 1220 are bore code 20, multiplied by 5 to give 100 mm.
What is the speed rating of 1220-K?
SKF lists a 7500 r/min thermal reference speed and a 4800 r/min mechanical limiting speed for 1220 K; real limits also depend on lubrication and fits.
How much misalignment can 1220-K tolerate?
Self-aligning ball bearings tolerate roughly 2–3° of static misalignment for open executions; sealed 2RS1 variants like 1220-K allow less (about 1°) because the seal lip binds first.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.