I have attached a blender file below along with some pictures. I tried to use the boolean modifier to do the same but came up with rather difficult to work with results. I want to have the curve and the shape of the hat to be nearly the same as the real Staunton Bishop.
gdrive link to blend file: https://drive.google.com/open?id=1x1poqr1abMpW_miAbRIkWpvRVR0twlMc