[Diabolical Artificer]

Fettling ali can be a pain, clogs small drills and files but I routinely do holes with the method David used without a vice, a drill and file is all you need, doesn't take long. A coarse file helps, the type they use for finishing horse shoes.

The problem with dremel type drills with cutting disks is that it's hard to start the cut and then maintain the cut without breaking the disk or it skipping and then ruining your finish. The little grinding bits get clogged and if your not careful bite into the ali.

It's well known that aluminium is Northumbrian cheese made on a grey cloudy winters day, the cheese goes grey as a result, they then roll it into sheets.

Andy.