W618-2 bearing: complete specifications & equivalents
The W618-2 is a ISO 15 radial bearing sized 2 x 5 x 1.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 2 mm |
| Outer diameter D | 5 mm |
| Width B | 1.5 mm |
| Material | SS440C |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 0.094 kN |
| Basic static load rating C0 | 0.025 kN |
| Fatigue load limit Pu | 0.001 kN |
| Reference speed (thermal) | 200000 rpm |
| Limiting speed (mechanical) | 120000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 0.1 g |
| Manufacturer designation | W 618/2 |
| 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 & 61800-series range
| Bore d | 0.079 in |
|---|---|
| Outer diameter D | 0.197 in |
| Width B | 0.059 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 1.5 mm |
| Smallest bore in 61800-series | 1 mm |
| Largest outer diameter in 61800-series | 1820 mm |
| Width range across 61800-series | 1–140 mm |
| Bore position in 61800-series (smallest first) | 3 of 74 |
| Bore above smallest 61800-series size | 1 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the W618-2 model number is decoded
The W prefix denotes SKF stainless steel deep-groove bearings (X108CrMo17 / AISI 440C class rings). In the 61800-series, the bore is written directly after the slash as 2 mm (bores below 10 mm use the slash spelling). Envelope 2×5×1.5 mm (0.079×0.197×0.059 in), C 0.094 kN, C0 0.025 kN, Pu 0.001 kN; limiting speed 120000 r/min and mass 0.1 g. The open W 618/2 carries no shields or seals and relies on application lubrication and external sealing. Stainless is chosen for corrosion and washdown duty, not for extra load — the same-envelope chrome-steel bearing rates higher.
Typical equipment & failure modes
Common applications
- pharmaceutical and packaging machines
- washdown-duty equipment
- chemical and marine atmospheres
- medical and laboratory devices
Known failure patterns
- surface staining and pitting when even the stainless steel is left unlubricated in salty or acidic duty
- seal and grease failure before the rings corrode in sustained washdown service
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
Selection pitfalls — read before you substitute
- W-prefix stainless rings (X108CrMo17 / AISI 440C class) resist moisture and weak chemicals but will still rust in chloride-rich or salt-spray duty without protection — W618-2 is not marine-grade stainless.
- The stainless steel is martensitic and MAGNETIC; do not reject W618-2 over magnetism — only austenitic grades are non-magnetic, and those are too soft for bearing raceways.
- Stainless bearings carry lower load ratings than chrome steel of the same envelope: W618-2 is quoted at C 0.094 kN versus the 1.5 mm-wide 52100 version — do not swap on dimensions alone.
- Food, pharmaceutical and washdown positions need food-grade grease (e.g. NSF H1 registered) inside W618-2; standard fill is industrial grease unless specified otherwise.
- Deep-groove geometry tolerates only minutes of misalignment; if the 5 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming W618-2.
- Fillet radii must clear the W618-2 chamfer so the 1.5 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
Frequently asked questions
What are the dimensions of the stainless W618-2?
SKF W 618/2 measures 2×5×1.5 mm (0.079×0.197×0.059 in), about 0.1 g, C 0.094 kN.
What does the W in W 618/2 mean?
W is the SKF prefix for stainless steel deep-groove bearings (rings in X108CrMo17 / AISI 440C class); the rest of the designation follows the normal series and bore rules.
Can I replace a chrome-steel bearing with stainless W618-2?
The envelope matches, but stainless rates lower (C 0.094 kN for W 618/2); for corrosive environments that trade-off is intended, for high loads it shortens life.
Is the stainless bearing magnetic?
Yes. Bearing stainless steels are martensitic (hardened) and magnetic; non-magnetic austenitic grades cannot be hardened enough for raceways and balls.
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.