[QUOTE=Giuliano]Both great ideas..
And as for punching a clean hole, compression-type hole punches really only work well for smaller holes, and larger hole saws can be difficult to use without a powerful hand drill or drill press.. neither of which I have.
How big a hole do you want to cut these go to 50mm.
The hole cutter you tried was proberly a cheaper one meant for wood they go blunt quick. If you try an electrial supply place (for trade users) or perhaps a plumbers merchant they sell hole saws to cut metal with and alluminium is real easy to cut. Watch when it breaks through or you end up with a twisted piece of metal spinning on the end of a hole saw