Thank Michael,

first thank you so much I now the problem now why I can't see the center because he is not exactly circular
the shape not sweep just Boolean from box how ever I think maybe there is something wrong with it so I re model it the good news here
1- BoundingBoxCenter command work great for me
2- Circles > 3pts snapping work good I never use this tool and now I will not stop use it :)
3- draw a line spanning across it and then use the midpoint of the line not sure but this one not work for me but I am sure is my problem maybe I don't understand it however my problem is fix so thank you so much you are always have the answer for my question.