618-7 bearing: complete specifications & equivalents
The 618-7 is a ISO 15 radial bearing sized 7 x 14 x 3.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 7 mm |
| Outer diameter D | 14 mm |
| Width B | 3.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 0.78 kN |
| Basic static load rating C0 | 0.26 kN |
| Fatigue load limit Pu | 0.011 kN |
| Reference speed (thermal) | 100000 rpm |
| Limiting speed (mechanical) | 63000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2.2 g |
| Manufacturer designation | 618/7 |
| 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 | 0.276 in |
|---|---|
| Outer diameter D | 0.551 in |
| Width B | 0.138 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 3.5 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) | 8 of 74 |
| Bore above smallest 61800-series size | 6 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| W618-7 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 7×14×3.5 mm envelope, but the stainless and chrome-steel executions carry different catalogue ratings (0.78/0.26 kN vs 0.663/0.26 kN) — envelope match, not a load-rating equivalent; choose by corrosion versus load duty. |
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 618-7 model number is decoded
In the miniature 61800-series, the bore is written directly after the slash as 7 mm (bores below 10 mm use the slash spelling). The envelope is 7×14×3.5 mm (0.276×0.551×0.138 in) with a 3.5 mm radial section height, C 0.78 kN, C0 0.26 kN and Pu 0.011 kN. The open 618/7 carries no shields or seals and relies on application lubrication and external sealing. Limiting speed 63000 r/min, catalogue mass 2.2 g. A thin section saves space but leaves little margin for misalignment or shaft deflection.
Typical equipment & failure modes
Common applications
- gearboxes and speed reducers
- centrifugal and positive-displacement pumps
- material-handling equipment
- industrial fans
Known failure patterns
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
- electrical pitting in VFD-driven motors without shaft grounding
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- Deep-groove geometry tolerates only minutes of misalignment; if the 14 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming 618-7.
- Mount by heating the inner ring (max 120 °C) — driving 618-7 home through the outer ring or balls brinells the raceways.
- Open 618-7 needs external sealing at the arrangement level; in dusty housings its life depends entirely on those external seals and the regreasing schedule.
- Plan a relubrication interval for 618-7; run-to-failure on open deep-groove bearings is the dominant early-failure cause.
- Clearance suffixes follow the seal code in the designation stack (e.g. 618/7-2Z/C3 in SKF spelling); no suffix means normal CN internal clearance.
- At 7 mm bore, C3 clearance is the safe choice when interference fits plus temperature rise consume the CN clearance; a hot tight bearing with no residual clearance fails fast.
Frequently asked questions
What are the dimensions of 618-7?
The SKF 618/7 measures 7 mm bore × 14 mm OD × 3.5 mm width (0.276 × 0.551 × 0.138 in), mass about 2.2 g. It is open, with no shields or seals.
Why is there a slash in the designation 618/7?
The slash writes a bore that falls outside the two-digit code table: 618/7 means 7 mm bore. The site slug 618-7 replaces the slash with a hyphen.
Which fits should I use for 618-7?
With a rotating inner ring use roughly j5/k5 on the shaft and H7 in the 14 mm housing; reverse the interference if the outer ring rotates.
How heavy is 618-7?
Catalogue mass is 2.2 g for 618/7; seal and cage executions of the same envelope differ by a few grams.
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.