How to drill a hole on diecast toy using dremel? I just bought a new-ray helicopter diecast toy. I want to modify it a bit, and one of the plan is to make holes for the windows (square, around 5mm by 5mm). What I'm thinking is to use dremel to drill a small hole (around 2mm diameter) and then enlarge the hole using dremel metal grinder bit. 
However, I'm not sure how to start. 
Dremel bit catalogue has drill bit for metal, for soft metal. I am not sure what kind of metal the diecast is. The thickness of the diecast is around 1mm.
I also checked dremel speed guide chart, but could not find the speed for drilling.

Is it ok to use these drill bits for that purpose? What speed should I use?
For delicate work in soft materials, I still like to use my old wheel brace (hand drill).  I've used it on plastics, wood and aluminium when I don't want to risk marring the surface as I break through.  Securing the workpiece is an absolute requirement as it's a two-handed tool.  I'd start with a 2&nbsp;mm drill bit, then use a 4&ndash;4.5&nbsp;mm bit so you've got the minimum at the next step.

You could then square off the corners with a needle file.  My square needle file is about 2&ndash;3&nbsp;mm at the widest point. This will give you much squarer corners than any rotary tool can provide.  Even if you start with the dremel, you may need to finish off with a needle file.