"Gerald Miller" wrote in message
...
snip----

My first end mill was a highly modified, very short 3/8" drill bit

I trust part of the modification was to grind the perimeter of the drill?

Drills are circular ground, and not backed off, unlike an end mill. As close
as they get is to have the lands narrowed, to minimize contact with the
hole. While you can get them to cut, they do it with considerable protest.
You'd have less than acceptable results with tough materials.

Harold