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 | — | — | Not tabulated here — see the note below. |
| 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.
Two series in the standard are not here
Diameter series 7 is the thinnest section the standard defines, and diameter series 1 sits between the 6000 and 6200 envelopes. Neither is tabulated in this library. Series 7 is absent because the catalogue tables that carry it disagree with each other: the one table long enough to be useful gives the 61700 series the same outside diameters as the 61800 series at the same bore, and two different diameter series cannot share an outside diameter. Something in that table is a copy error, and nothing in it can be trusted enough to tabulate. Series 1 has simply not been compiled yet. Both absences are stated rather than left as blank rows: 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. 6 is a single-row deep groove ball bearing, which is the only type tabulated here, so every designation in this library carries it.
- 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 one family whose designation does not divide this way
The 16000 series is the exception in this library. 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. The form does not decompose, and the outside diameters make the family's position clear anyway: a 16004 and a 6004 are both 42 mm across, and the 16004 ring is 4 mm narrower. Because the designation cannot be reconstructed by string assembly, this library stores the form as a field on the series and reads it, rather than deriving designations.
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.