[R-390] Holy terror

[Rasputin Novgorod]

I have to put several holes, round and rectangular in
an old chassis about inch size. I do have two chassis
punches, but the wrong sizes. In the past I've tried
drawing the hole onto the metal, then drilling, filing
and power jigsawing to the lines. 

I also have a dremol tool.

Any suggestions about doing this? It's a populated chassis
and I don't really want to spray steel filings and chips
all over it; nor do I want to have to dissassemble
too much.

Perhaps some kind of compact, powerful nibbler?


Sincerely
/b