7 1/4 to 8 1/4 Swap

Tooljunkie said
Its called a die grinder,with a carbide burr. Will hog out that 1/2 of a hole in seconds. Theres all kinds of shapes and sizes of burrs as well as die grinders,air and electric.
Very handy.

So a Dremel with carbide should do it? Glad it sounds like I can get this done at home, I was getting frustrated with all of the complications