We try to avoid custom machining when possible because if something goes wrong in the middle of nowhere, odds are good that a shop able to do the machining is far away. The Dodge rotors were used on trucks with Unitbearings and won’t fit over a serviceable hub configuration. The center hole as-shipped is 3.09 inches and needs to be opened to 3.87 inches to fit over the back of the hub. We had our neighbor do the work on a mill, but any shop with a lathe big enough to accept the rotor can do it. Notice the chamfer (angle) of the new hole. It will be used at our next brake job so the parts store can chock the rotor up to resurface it.