ISO 104 covers boundary dimensions of thrust bearings. This page sets out what the standard fixes for 51200 series thrust ball bearings, what it deliberately leaves to other documents, its national equivalents, and the dimensional table supplied against it.
ISO 104 — Scope
ISO 104 fixes the boundary dimensions of thrust bearings: the shaft washer bore d, the housing washer outside diameter D and the assembled height H — the dimension the shoulder spacing has to be machined to. Double-direction bearings add the second bore d2 for the centre washer.
What ISO 104 Does Not Fix
It does not rate the bearing (ISO 281 for the dynamic rating, ISO 76 for the static one), and it says nothing about the minimum axial load a thrust bearing needs in order to keep its rolling elements running rather than sliding.
This division of labour is the thing to carry away from any bearing standard. A boundary dimension standard makes bearings interchangeable; it does not make them equivalent. Two bearings of the same designation from different makers mount in the same seat and are not required to have the same load rating, the same internal design, the same cage or the same speed limit.
Dimensions Supplied to ISO 104
| Designation | Bore d (mm) | Outer diameter D (mm) | Height H (mm) | Chamfer r min (mm) |
|---|---|---|---|---|
| 51200 | 10 | 26 | 11 | 0.6 |
| 51201 | 12 | 28 | 11 | 0.6 |
| 51202 | 15 | 32 | 12 | 0.6 |
| 51203 | 17 | 35 | 12 | 0.6 |
| 51204 | 20 | 40 | 14 | 0.6 |
| 51205 | 25 | 47 | 15 | 0.6 |
| 51206 | 30 | 52 | 16 | 0.6 |
| 51207 | 35 | 62 | 18 | 1 |
| 51208 | 40 | 68 | 19 | 1 |
| 51209 | 45 | 73 | 20 | 1 |
| 51210 | 50 | 78 | 22 | 1 |
| 51211 | 55 | 90 | 25 | 1 |
| 51212 | 60 | 95 | 26 | 1 |
| 51213 | 65 | 100 | 27 | 1 |
| 51214 | 70 | 105 | 27 | 1 |
| 51215 | 75 | 110 | 27 | 1 |
| 51216 | 80 | 115 | 28 | 1 |
| 51217 | 85 | 125 | 31 | 1 |
| 51218 | 90 | 135 | 35 | 1.1 |
| 51220 | 100 | 150 | 38 | 1.1 |
National Equivalents
DIN 711 and DIN 715 cover single and double direction thrust ball bearings, DIN 722 and DIN 728 the roller types; GB/T 301 is the Chinese equivalent for thrust ball bearings.
This product is supplied against ISO 104 / DIN 711 / GB/T 301, which names the documents it is made to.
When to Cite ISO 104
ISO 104 is the international reference and the right one to cite on a new drawing or a purchase specification. Adding the national equivalents alongside it costs nothing and makes the requirement legible to a supplier working to DIN or to GB/T.
