For those who may look up this info.......the earlier versions of the 6230 lathe,(and many others),while appearing to have standard metric bearings ,in fact have a spindle bearing,both ends,that has a tapered outside diameter of the cup,rather than cylindrical,and seats in a taper in the casting........These are not available,and replacements must be made ,(taper ground),or the casting reworked....I do not know when the change to standard bearings occurred.