NACHI 6308 dimensions and model data
NACHI 6308 is a catalogue-listed deep groove ball bearing measuring 40×90×23 mm (bore d × outside diameter D × width B), with open.
Reading this exact marking
In the base number 6308, 6 identifies the deep groove ball bearing type and 3 is the diameter-series digit. The bore code 08 corresponds to the 40 mm bore in this model row; it is not itself a diameter in millimetres.
The base designation is 6308. No closure suffix is listed: this is the open version. NSE/NSE9 denotes a contact seal; NKE/NKE9 denotes a non-contact seal. ZE and ZZE distinguish one and two shields. Do not silently remove the 9 or the leading 2 when matching a model.
Lubrication-qualified speed
The applicable grease-lubricated limit is 7800 r/min. The oil-lubricated limit is 9200 r/min.
Load calculation reference
This row supplies f0 = 13.2. For positive radial load Fr, select the catalogue factors using f0×Fa/C0r, with Fa and C0r expressed in the same force unit. If Fa/Fr ≤ e, Pr = Fr. Above e, Pr = 0.56Fr + YFa. For the static check use P0r = max(Fr, 0.6Fr + 0.5Fa).
Catalogue factors and limits
| f0×Fa/C0r | e | Y above e |
|---|
| 0.172 | 0.19 | 2.30 |
|---|
| 0.345 | 0.22 | 1.99 |
|---|
| 0.689 | 0.26 | 1.71 |
|---|
| 1.03 | 0.28 | 1.55 |
|---|
| 1.38 | 0.30 | 1.45 |
|---|
| 2.07 | 0.34 | 1.31 |
|---|
| 3.45 | 0.38 | 1.15 |
|---|
| 5.17 | 0.42 | 1.04 |
|---|
| 6.89 | 0.44 | 1.00 |
|---|
The table gives discrete reference points, not a universal Y value. No interpolation or extrapolation rule is asserted here; verify intermediate conditions against the applicable engineering method. The Fa/Fr branch test is undefined when Fr is zero.
Versions listed alongside 6308
Selection limits and missing data
- The catalogue row gives Cr = 51.5 kN and C0r = 24.1 kN. These are load-rating inputs for calculations, not a statement of maximum permissible service load.
- The adjacent shaft shoulder must meet da ≥ 49 mm, the housing shoulder Da ≤ 81 mm, and the adjacent fillet ra ≤ 1.5 mm for the illustrated mounting geometry.
- The 0.633 kg mass is reported once for the shared catalogue row; separate masses for each closure version are not published in this table.
- A catalogue speed limit does not approve the actual operating speed: load, lubrication, fits, temperature and surrounding hardware still need checking.
- The listed marking does not establish a particular internal clearance, ABEC grade, temperature range or grease life. Extra ordering suffixes must be checked separately.
- Matching boundary dimensions is only a starting point for comparison, not proof of interchangeability or equipment fitment.
Technical basis:NACHI Deep Groove Ball Bearings, catalogue B3402E-2, imprint 2026.7; physical PDF pages 3–5. Source checked 2026-10-02. Facts are independently organised for query and comparison; the original PDF and illustrations are not redistributed.
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