6238 Single-row Deep Groove Ball Bearing
6238 is a single-row deep groove ball bearing, light series, with a 190 mm bore, a 340 mm outside diameter and a 55 mm width. Those numbers — the bore, outside diameter, width and the 4 mm minimum chamfer — are ISO 15 standard values, identical for every manufacturer.
Dimensions
All 6200 Series designations- Designation
- 6238
- Type
- Single-row deep groove ball bearing — radial
- Series
- 6200 Series (light)
- Bore code
- 38 — 190 mm
- Bore d
- 190 mm (7.4803 in)
- outside diameter D
- 340 mm
- width B
- 55 mm — the assembled width
- Chamfer, r s min
- 4 mm — minimum, not nominal
- Radial section
- 75 mm = (D − d) / 2
Nominal values in millimetres as published in ISO 15, the boundary dimension plan this type is tabulated in. The chamfer figure is the minimum single chamfer dimension the plan gives (r s min); the matching maximum is in ISO 582 — which is why the row says “min” and not an equality. A bearing that has been fitted with shields or seals carries the same dimensions, because none of the suffixes touches the boundary dimension plan.
Reading the designationwhere 190 mm comes from
The designation is three fields: type, the series and the bore code. For codes 04 and above the bore is the code multiplied by five, which is why 38 gives 190 mm. The four exceptions are 00, 01, 02 and 03 at 10, 12, 15 and 17 mm.
Position in the series31 of 32 in 6200 Series
Radial internal clearanceISO 5753-1, bore 180–200 mm
| Group | Radial internal clearance | When it is used |
|---|---|---|
| C2 | 2–30 µm | Tighter than default; for fits that already take up the clearance. |
| CN (normal) | 25–71 µm | The default — usually not marked on the bearing at all. |
| C3 | 63–117 µm | Interference fits, electric motors, hot inner ring. The common upgrade. |
| C4 | 107–163 µm | Heavy interference fits and high-temperature service. |
| C5 | 150–230 µm | The loosest group in the table; special applications. |
Values are the pre-mounting radial internal clearance for a deep groove ball bearing with a cylindrical bore, in micrometres, from ISO 5753-1. Pressing the inner ring onto a shaft and running the inner ring hotter than the outer ring both close this up — an interference of a few micrometres is a few micrometres straight out of the running clearance, which is the whole reason C3 exists. For this bore, normal (CN) is 25–71 µm and C3 is 63–117 µm.
What is deliberately not publishedwhy there is no load rating here
No load rating, no limiting speed and no mass appears on this page. Those are catalogue values rather than standard values: ISO 281 defines how a dynamic rating is calculated, not what it comes out as, and the result depends on internal geometry — ball or roller diameter, the complement, raceway conformity — that none of the boundary dimension plans (ISO 15, ISO 355, ISO 104) fixes. Published catalogue figures for one and the same designation differ between makes by several percent at these sizes, and limiting speed additionally depends on lubrication and on whether the bearing is open, shielded or sealed. Publishing any single figure here would dress a catalogue entry up as a property of the designation. Take the rating from the catalogue of the bearing you actually buy.
The dimensions above are a different matter, and they are the reason a designation is worth anything: the boundary dimensions — bore, outside diameter and the section dimensions of the plan this type is tabulated in, plus the chamfer minimum where that plan gives one — are fixed by the standard, so every maker's bearing of this designation fits the same shaft and the same housing.
Same bore, every series and typewhat a 190 mm shaft would take instead
| Designation | Series | Type | D | Overall size (B / T / H) | Section (D − d)/2 | vs 6238 |
|---|---|---|---|---|---|---|
| 6238 | Light — this bearing | Deep groove ball | 340 | 55 B | 75 | — |
| 6038 | 6000 Series — Extra-light | Deep groove ball | 290 | 46 B | 50 | -50 mm on D |
| 6338 | 6300 Series — Medium | Deep groove ball | 400 | 78 B | 105 | +60 mm on D |
3 series across one bearing type, one bore: the shaft diameter is the same in every row, so the only thing that changes is what the housing and the axial space have to accommodate. Outside diameter and the overall size are standard boundary dimensions in the plan each type is tabulated in (ISO 15 / ISO 355 / ISO 104) — the same figure for every manufacturer. The section column is derived as (D − d) / 2. Load capacity rises with the outside diameter, but the figure itself has to come from the manufacturer’s catalogue for the bearing you actually buy — see above.