1-1c. Surface roughness

 The effective interference obtained after fitting differs from calculated interference due to plastic deformation of the ring-fitting surface. When the inner ring is fitted, the effective interference, subject to the effect of the fitting surface finish, can be approximated by the following equations:

(In the case of a ground shaft)deffd d/(d+2)
(In the case of a turned shaft) deffd d/(d+3)

where:    
deff: effective interference mm
d: calculated interference mm
d: bore diameter of bearing mm