61917 Deep Groove Ball Bearing
61917 is a single-row deep groove ball bearing, thin series, with a 85 mm bore, a 120 mm outside diameter and a 18 mm width. Those four numbers — bore, outside diameter, width and the 1.1 mm minimum chamfer — are ISO 15 standard values, identical for every manufacturer.
Dimensions
All 61900 Series designations- Designation
- 61917
- Type
- Single-row deep groove ball bearing
- Series
- 61900 Series (thin)
- Bore code
- 17 — 85 mm
- Bore d
- 85 mm (3.3465 in)
- Outside diameter D
- 120 mm
- Width B
- 18 mm
- Chamfer, r s min
- 1.1 mm — minimum, not nominal
- Radial section
- 17.5 mm = (D − d) / 2
Nominal values in millimetres as published in ISO 15, the boundary dimension plan for radial bearings. 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 four dimensions, because none of the suffixes touches the boundary dimension plan.
Reading the designationwhere 85 mm comes from
The designation is three fields: type, diameter series and bore code. For codes 04 and above the bore is the code multiplied by five, which is why 17 gives 85 mm. The four exceptions are 00, 01, 02 and 03 at 10, 12, 15 and 17 mm. This one is also sold as 6917 — the same series under the other naming convention, where 61800 is the SKF / FAG form and 6800 the NSK form. Both designations take the same 85 mm shaft and the same housing.
Position in the series18 of 21 in 61900 Series
Radial internal clearanceISO 5753-1, bore 80–100 mm
| Group | Radial internal clearance | When it is used |
|---|---|---|
| C2 | 1–18 µm | Tighter than default; for fits that already take up the clearance. |
| CN (normal) | 12–36 µm | The default — usually not marked on the bearing at all. |
| C3 | 30–58 µm | Interference fits, electric motors, hot inner ring. The common upgrade. |
| C4 | 53–84 µm | Heavy interference fits and high-temperature service. |
| C5 | 75–120 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 12–36 µm and C3 is 30–58 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 diameter, ball complement, raceway conformity — that ISO 15 does not fix. 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: bore, outside diameter, width and the chamfer minimum are fixed by ISO 15, so every maker's bearing of this designation fits the same shaft and the same housing.
Same bore, other serieswhat the 85 mm shaft would take instead
| Designation | Series | D | B | Section (D − d)/2 | vs 61917 |
|---|---|---|---|---|---|
| 61917 | Thin — this bearing | 120 | 18 | 17.5 | — |
| 61817 | 61800 Series — Ultra-thin | 110 | 13 | 12.5 | -10 mm on D |
| 6017 | 6000 Series — Extra-light | 130 | 22 | 22.5 | +10 mm on D |
| 6217 | 6200 Series — Light | 150 | 28 | 32.5 | +30 mm on D |
| 6317 | 6300 Series — Medium | 180 | 41 | 47.5 | +60 mm on D |
5 series, 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 width are ISO 15 standard values; 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.