Fossil preservation techniques and materials, a short question

[FossilDude@xxxxxxx]

I have a question concerning the best method of removing delicate fossils
from a hard micrite mud matrix (black limestone, incase some of you are more
familiar).  This matrix is very hard, and it fractures conchodially, and in
it are some very delicate ammonoids I am to study this summer.  I have been
chipping away at these samples with a hammer, and it frustrates me when I
look at a newly chipped edge to find a nice large ammonoid, not in so good a
shape.  So, I figure I would do well in investing in a dental drill, or other
drill of some sort.  I was wondering if anyone here could point me in the
direction of a reasonably affordable set up.

JH