The groove is cast in, i have to just clean the walls and bottom. I can write it by hand but i want to be able to use the wear offset to control my diameter dimensions.

Cast groove finish dim's are 315 mm OD dia and 261.6 mm id dia and 11.98 m deep. There is approx 2.54 mm cast stock on all three sides. I want to be able mill each side and drop my Z depth on each pass. I just have not been able to fine an option on $x to do that. I want to control the diameter with a wear offset. I am just trying to keep it as simple as possible. I have a series of castings I have to do this to.

I have a simple question, I have to mill a round groove in a casting. The rough groove is cast in and I have to clean up the side walls and bottom. I do not have a model of the part just a print. To the question, how do draw it and then what toolpath do I use to process it? I am using Mastercam 4x. Can someone help. Thanks Pat