It really depends on what you will use it for and how often. I use my drill
presses every day, but I still don't feel its often enough to setup a
coolant system on them. A few holes, a few threads, next... I've found
that unless I am doing heavy drilling a single drop of Tap Magic is enough
to lubricate my cuts. A pint bottle by the drill press area lasts a very
long time. Even given that its hard to get just one drop. If I am doing
heavy drilling I use a heavier oil, but still only a few drops at a time
unless it?s a hole down inside a blind cavity so that I can contain a little
more oil. On the other hand... I'm not a real machinist. Probably 50% of
what I know I learned from the guys in this group.
Something to think about though. One of the old members of this groups uses
the same soluble coolant for just about everything. Turning, milling,
drilling, etc. But on the lathe and the drill press he dips a cup out of
the tank on the mill and applies it with a brush.