ISO 15 — Boundary dimensions, general plan
The plan behind every size in this library: which bore, outside diameter and width combinations count as standard, and how the digits of a designation point at one of them.
What it fixes
ISO 15 sets the mounting envelope of a radial bearing: the bore d, the outside diameter D, the width B, and the minimum single chamfer r s min at the ring corners. It describes nothing inside the bearing. Two bearings carrying the same designation are dimensionally interchangeable by definition — that is the whole point of a plan — which is why a bearing can be ordered across borders on its designation alone. The standard tabulates eight diameter series, numbered 7, 8, 9, 0, 1, 2, 3 and 4, in Tables 1 to 8. Each table holds the dimension series built on that diameter series.
The eight diameter seriesand which of them this library tabulates
| Diameter series | Series in this library | At 20 mm bore: D × B | Note |
|---|---|---|---|
| 7 | 61700 | 27 × 4 mm | — |
| 8 | 61800 | 32 × 7 mm | — |
| 9 | 61900 | 37 × 9 mm | — |
| 0 | 6000 | 42 × 12 mm | The 16000 family is not a second diameter series: it shares these outside diameters in a thinner ring. |
| 1 | — | — | Not tabulated here. |
| 2 | 6200 | 47 × 14 mm | — |
| 3 | 6300 | 52 × 15 mm | — |
| 4 | 6400 | 72 × 19 mm | — |
The third column is read from this library's own bearing data, not copied from the standard, so it moves if the data moves. It is the clearest statement of what a diameter series is: at one bore, the outside diameter steps up series by series.
One series in the standard is not here
Diameter series 7 — the 61700 — is the thinnest section the standard defines, and it is tabulated in this library: 21 designations, 10 to 100 mm bore. An earlier version of this page said it was absent because the catalogue tables that carry it disagree with each other, one of them giving the 61700 the same outside diameters as the 61800 at the same bore. The ISO 15 table itself settles that: a 61700 is 15 mm across on a 10 mm bore against 19 mm for the 61800, so the series is a rung of its own and the catalogue list was simply short, not wrong at the small end. Diameter series 1 is not tabulated here: it is absent from the catalogues checked rather than from the standard. That absence is stated here rather than left as a blank row — a gap that says why it is a gap is useful, and a gap that pretends to be the whole ladder is not.
Reading a designationthe three parts ISO 15 assumes
- Type
- The first digit, in the families that write one. 6 is a single-row deep groove ball bearing; 3 and 5 are the tapered roller and thrust ball plans, which are not part of this one. The self-aligning ball bearing is type 1, and its four families are the only ones here that do not all print it — see the next section.
- Dimension series
- The next digits: width series first, then diameter series. Both digits are printed in the thin families — 61804 carries 18, meaning width series 1 on diameter series 8. In the 60, 62, 63 and 64 families the width digit is not printed, so only the diameter digit is visible: 6204 shows 2 for diameter series 2.
- Bore code
- The last two digits. From 04 upwards, multiply by 5 to get the bore in millimetres: 04 is 20 mm, 10 is 50 mm, 20 is 100 mm.
- Bores of 10, 12, 15 and 17 mm
- Coded 00, 01, 02 and 03. The multiplication rule does not run below 04, so 61800 is a 10 mm bore and not a 0 mm one. Getting this wrong is invisible in a table: the row still reads as a bearing.
The designations this library stores rather than assembles
Five of the families tabulated here are stored as a form rather than assembled from parts, and they are not stored for the same reason. The width series 16000 is the plain one: reading 16004 with the rule above gives width series 1 on diameter series 6, and ISO 15 tabulates no diameter series 6 — its eight tables are 7, 8, 9, 0, 1, 2, 3 and 4. Its position is clear from the outside diameters anyway: a 16004 and a 6004 are both 42 mm across, and the 16004 ring is 4 mm narrower. The four self-aligning families — 1200, 1300, 2200 and 2300 — are a different case: they do divide into a type code and a series, but one of the two digits is left out of the printed form, so the same position carries a different field from family to family. They are all type 1, and in the 1200 and 1300 families the width series is 0 and is never printed, so a 1204 reads as 1 (the type code), 2 (a diameter series) and 04 (the bore code) — the same three fields a 6204 has, with 1 in place of 6. In the 2200 and 2300 families it is the type code that goes unwritten: a 2204 leads with 2, which is there a width series, and then 2 again for the diameter series. The same position is therefore a type code in one family and a width series in the next, and nothing in the number itself says which. That is exactly why the form is stored rather than assembled. The four share their diameter series with the deep groove families — 1200 and 2200 on diameter series 2, which the 6200 uses, and 1300 and 2300 on diameter series 3, which the 6300 uses — which is why their outside diameters repeat those figures row for row.
What ISO 15 deliberately does not fix
Not the load rating, not the limiting speed, not anything about the balls or the raceway geometry. Two bearings that share a designation share a mounting envelope and nothing else — their dynamic load ratings can differ by several percent between manufacturers, because the rating depends on internal dimensions the plan does not constrain. That is why this library publishes no load ratings at all.