of making holes in silver.

I'm trying to make two holes 7mm apart in a strip of silver 1.7mm thick and 5mm wide. I need to make them big enough to get 2mm wire through. Every time I've done this it's been a nightmare. I use drills, pointy tip burrs and today I punched through with nails. Why is something that should be so easy so difficult? What am I doing wrong?