The column has degree markings. The thing is, think about it. YOur tilting a great part of the mill rather than just the workpiece. Unscrewing that thing and then loosening the column, making sure it does not crash on the ground, its a pain.
If you want real accuracy, the best way to go is a sine vise. They are available through the usual retailers. Sine vises look like a regular screwless vise, but they have a tilting side. And then you get these things called sine bars, which are accurately ground blocks. Using some basic trig. you put the bar underneath the pivoting part of the vise. Now you have an angle
