Slot drills

I recently was given a book called "The CNC Workshop" which teaches
CNC programing. I haven't had time to go throught the entire course
but I have loaded the software from the included CD and played with
the CNCez milling simulator. I created a test part in Vector, saved
it as a DXF file and then used ACEconverter to generate the g-code. A
little editing in Notepad to select the tools and speeds and then
load that into the milling program to create virtual chips. Great fun.

One thing that I noticed is that the default tool library for the
mill program has both end mills and slot drills. I've heard
references to slot drills over the years but never knew exactly what
they were. Neither J&L or McMaster-Carr seem to carry them. Does
anyone have a good explanation for what they are? I asked one of my
professional machinist buddies and he'd never heard of them.

Dan Eaton (Saint Louis)