Hi Greg,

For the 1/8" slotting of the bar stock I used an 1/8" end mill. If you have a sturdy drill press, it should be okay on aluminum. You just have to hold it in a drill press vice and slide the whole thing forward. Be very careful, the end mill will cut fingers very quickly (it's nothing like bumping into a drill bit)!! Purchase a "center cutting" 1/8" end mill (with a 3/8" shank and 1/2" flute length) and try plunging it in like drilling a series of holes, then slide it along clearing out the slot. Attach some sort of guide fence to the drill table for straight work. Cut slowly so it doesn't grab the work.

Roger

((Make that a 4-flute end mill. It will be easier to control the cut))