Steel T-slot plate

SureFrame T-Slot Aluminum Extrusion t slot steel When machining a T-slot in cast iron, are you better off roughing out the slot to full depth first? Or should you leave solid metal for the T- t slot panel When machining a T-slot in cast iron, are you better off roughing out the slot to full depth first? Or should you leave solid metal for the T-

twin33 slot I'm making a steel faceplate for my 4th axis and my metal lathe, with T slots like those on my