Just to true up the surface, maybe .005" to .030".
If you're removing material, it depends on the spindle power available and the bending strength of the tool. With that tool, maybe 1/4" on a common Bridgeport.
I used to work next to a spar milling shop, where they got fired for taking a cut less than 1/2" deep. They used snow shovels to pick up the chips when they got knee-deep on the floor, which happened several times a day.
Mike Halloran
Pembroke Pines, FL, USA