BTW- if anyone knows that this will mess up a mill, please post it and I will erase this thread. I talked to a couple of guys who didn't seem to think it would, but they are no final authority on anything.
One thing you may want to do someday is check the tram on the head. After periods of drilling and milling, the vibration can move the head. I do not know what type of mill you have but on the better mills the tram will change. On the cheaper mills I know it definately will. How do I know? I have run mills almost all my life. If you do not know how to check the tram, you will need a dial indicator, and a longer extension for the indicator. Center your mill table with the quill (remove the vise first) and set the indicator so it will reach the back of the table then swing it around 180 degrees to see if it reaches the front of the table. Adjust accordingly. Now that it does, touch the top of the table and set the indicator at "0". Swing the indicator in a 360 degree circle. All four points (north, south, east, west) must read zero. Adjust you head on the mill until it does. Most mills have 4 bolts in the front to rotate the head and usually three on the side to tip the head. Make sure they are tight after adjusting. After that, remount your vise and indicate it back in and you are on your way.