About this 3D model

I've added a hemicylinder to make this a knob with a D shaped fitting to replace a broken knob on a crock pot. At the given scale, the knob will fit a D where the diameter of the (imagined complete) cylinder is 1/4 an inch; the void is thus the radius or 1/8 an inch. This is in progress until I determine if the D needs to be inset for flush mount.