47-59 Machinist question??

[8man]

I have a piece of 1/4" thick x 3" long x 2" wide aluminum. I want to cut a piece out of the middle that is 3/4" wide x 2" long.

I am working with scrap right now, trying to build Ogre's door wiring bracket/thing. Once I get this figured out, I'll build the real ones.

First, I drilled a series of hole in the corners, getting up to 5/16". Then I started with a Dremel with a cut off wheel, but it won't cut all the way through the aluminum, it does not have enough blade clearance between the aluminum and the handle of the Dremel to cut all the way through the aluminum. I have a scroll saw with a metal blade, but it is really hard to control on this small piece to get any accuracy, but I did get a piece cut out with the scroll saw, but it was a really inaccurate cut.

Then I started filing, but the file is clogging up with the aluminum.

So, what is the best way to do this? And what do you do to get aluminum out of a good file?

Thanks.