Why is the 2600 stud not sitting completely flat on the surface of the plate?

it has always been this way that there is a small gap of 0,25 +/-0,1 so: 0,35 or o,4mm is ok. The outer edge of the collar can be irregular depending on the deep drawing process which can lead to scratches on the surface…. Therefore it is the way as it is with the gap. In addition the grip tolerances are tighter with this design! Also: the grip definition depends on this set up! In case a customer can't accept the gap he has to chamfer the bore but has to double check the grip!