I recently turned a 17" platter from Sycamore that was sliced from the end of a log. It was fairly wet, but not freshly cut. Turned to about 5/16 , it did not crack, but raised up a slight mound around the pith which was slightly off center. This was about 10 weeks ago and I still haven't decided whether to sand out the raised 4" dia section or leave it. I have also turned walnut platters end grain with success.