I don't think I was clear. I am dimensioning in a drawing. It is actually an assembly, with two parts (we can imagine them as two half-rings, for simplicity's sake) coming together to form the circle I want to dimension. The two "rings" will be bolted together for boring. I'd really like to put the dimension of the bore inside that circle. However, like I explained before, I've tried a lot of things and the dimension keeps "snapping" back to the center of that bore, right over the center mark. Ideally, I'd put that dimension somewhere between the center of the bore and the bored surface.