Cutting an old Chassis?

[LustandFury]

What exactly do you use to cut straight lines in an amp chassis? I want to install a IEC chassis plug so I need to free hand cut a squarish type hole for it like this...
http://upload.wikimedia.org/wikipedia/en/8/8f/IEC60320_C14.jpg
What should I use?

[GearHeadFred]

I did mine by drilling small holes around the parimeter and then filing it out... Low-tech old school!

[LustandFury]

I was thinking there would be a Dremel bit that might work?

[SatelliteAmps]

Dremel with a cutoff wheel. Wear safety glasses.

[LustandFury]

Thanks I found the cutting wheel on the web. Safety glass are always on!