Choosing a housing when all you know is the shaft
The plate is worn, the bearing designation is unreadable and the machine is down. What is left is a caliper. Here is the path from a measured shaft to a specific housing — and the traps along the way.
Where to measure
Measure the shaft at the bearing seat, not next to it. Shafts are often stepped, and five millimetres is a different housing size.
Measure in two perpendicular planes. A worn shaft goes oval — if the readings differ by more than a few hundredths, the shaft needs reconditioning, not a new bearing.
If the bearing sits on an adapter sleeve, the shaft diameter is smaller than the bearing bore. With a sleeve you measure the shaft, not the sleeve.
Write down what you measured, not what you rounded to. The catalogue works in standard sizes anyway.
Why through the bearing, not the housing dimension
It would seem simpler: you know the shaft, so look for a housing with that diameter. It does not work, for a mundane reason.
The manufacturer's catalogue gives the shaft diameter for only some of the items — the rest are described by body dimensions. Searching on the housing field would return a handful of results and miss most of the fits.
So the path is longer but certain: shaft → bearings with that bore → housings that take those bearings. The last step comes straight from the manufacturer's catalogue, which states which bearing goes into which housing.
Three things to check before ordering
Bearing type. Split housings take spherical roller and self-aligning ball bearings — not plain deep-groove ball bearings. If a 6208 was in the machine, a split housing is not the answer.
Mounting method. The bearing may be pressed onto the shaft or sit on an adapter sleeve. That is two different housing sizes for the same shaft diameter.
Seal. Felt is good to 4 m/s circumferential speed. Above that: lip to 8 m/s, then labyrinth. With dust: taconite.
Diameter alone is not enough. Bearing type and mounting method narrow it down just as hard.
Do it here
Our selector walks exactly that path: enter the measured diameter or the bearing designation and the result is grouped by housing series. Every item links to a page with dimensions from the manufacturer's catalogue.
If your diameter is in the standard series, we have a ready page listing every matching housing — one you can send to a colleague without explaining what to type.
Source
Selection path and housing-to-bearing assignment: HFB catalogue 2011/03. Seal speeds: page 6 of the same catalogue.