I need to make some square ( approx. 50*100 mm ) and round ( approx. 75mm
diameter ) holes in either 2 mm steel or 3 mm aluminum sheet..

I can cut the round holes using a holesaw ( bimetal body, carbide tipped )
in the drillpress, but how do I cut the square holes with a good result?

I have a drillpress ( cheap one ), but I am willing to invest some money (
not a fortune though ) in the proper tools if needed.. A CNC mill would be
nice, but not quite within the budget .-)

Any suggestions will be appreciated

/peter ( another one of those weird scandinavians )