Originally posted by AndyF
I used a cuttoff wheel on my Dremel to make the initial holes and then used the 1/2" and 1/4" sanding drums to round the corners and open up the holes. It worked great! Remember measure twice and cut once. 
Andy
Thanks Andy!
On the cut-off wheel --- slow speed or fast. Is there any tendency of melting.
Does it make a lot of fine dust? I seem to remember reading some cautions on respiratory risks.
Steve