Flycut the top of the dovetail flat.

Mill the flat next to the dovetail.

Next make cleanup cuts through the rough cast surface.

The next step is to center the pivot in the four jaw chuck and cleanup the pivot and base surfaces. Then the pivot is turned to 1.999 inches in diameter 0.625 inches thickness and the base pin is turned to 0.470 inches in diameter and 0.250 inches length.

Then the groove is cut in the pivot to provide a land for the clamping pins.