Under normal operating conditions the shaft seats for Y-bearings with grub screws or an eccentric locking collar should be machined to an h7 tolerance.
For light loads and low speeds an h8 shaft tolerance is sufficient and for very simple applications shaft tolerances from h9 to h11 may be used, as recommended in table.
For Y-bearings on an adapter sleeve, a shaft seat machined to h9/IT5 is adequate.
For Y-bearings with a standard inner ring the same recommendations apply as for standard deep groove ball bearings, e.g. tolerance j6 for light loads.
The location of the most commonly used ISO tolerance grades relative to the bearing bore are illustrated in fig 1.