Nice job, but May I ask would it be better to use "milling bits" instead of drill?
If at low speed and you hold it tight, that should work.

Yeah, it would have been nicer had I a larger bit, router bit or the like to use. I actually bought a nice 2.5" tall router bit for use in my router table, only to learn the shank was too big (1/2"). I didn't want to go out and spend more money on the project, so this worked. It was actually kind of fun...time consuming...but fun.