The width of the supporting surface must be at least equal to the width of the ring it supports
Permissible flatness deviation and deflections in supporting structure.

In order to make the slewing bearing turn smoothly, the mounting structure should be stress-relived after welding procedure, The maximum permissible out-of-flatness, including slops and axial deflections is detailed in the respective tables. See table 1
Regarding the slope of the machined surfaces, the figures shown in the table refer to a support width of 100mm. another important factor is to ensure that the maximum value is reached only once per 180°sector.

As in the case of out-of-flatness, any deflections in the supporting structure must not allowed to lead to localized buckling which might cause tight spots in the raceways. This could easily lead to over-loads. For this reason, the same conditions as for the out-of-flatness will apply.
For the maximum permissible deflections in the Table 2, the permissible slope may be twice the value”P” in Table 1 (Reference width 100mm)
The maximum permissible axial deflections “V” shown in Table 2 apply to all bearings types and are indicated as a function of the track diameter of the bearing