This part of IEC 60424 gives guidance on allowable limits of surface irregularities of ferrite cores.
This standard is considered as a general specification useful in the negotiation between ferrite core manufacturers and customers about surface irregularities.
BS EN 60424-1:2000 history
2016BS EN 60424-1:2016 Ferrite cores. Guidelines on the limits of surface irregularities. General specification
2000BS EN 60424-1:2000 Guidance of the limits of surface irregularities of ferrite cores - General specification