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I have a Crusader II (anilam), no "spiral" command,
it will do CW or CCW arcs.

You have to specify Start X,Y, End X,Y, and center
X,Y.

I am trying to cut a spiral into a piece of metal.
1/2" cutter, with 1/4" of steel between each
cut.

Can anyone recomment a CAD program or tell
me the math I need to use to program this into
my machine?

A spiral has several arcs, all from different
center points. I need to know the start X,Y,
end X,Y, and center X,Y for each of these
arcs.

Any help appreciated.

Google for Archimedan spiral and you should find some links that will help
with the design.

The basic formula is something like:

r = b * theta^a

where r = the radius,
theta = the angle in the X-Y plane
b = a scaling factor
a = coefficient that determines the degree of the spiral

Work out the values of "r" for different angles (theta in radians, I think)
and from that calculate the X-Y coordinates for various points. Play with
"a" and "b", to get the right number of spirals and distances between.

We did this at work for a small, flat-sheet, lab-scale membrane housing a
while back. We wanted a spiral groove in the face plate to direct fluid
flow in a spiral out from the center inlet to the outlet at the periphery of
the circular membrane. If it would help, I can email you the Excel
spreadsheet I used to calculate the coordinates that made up the curve. I
used a mechanical 3-D program (Alibre) to generate the dimensioned part with
the spiral groove, importing the coordinates from Excel to define the path
of the spiral. From there a DWG file was exported and sent off to the
machinist, who had no problem making the part. That's probably a lot more
work and expense than is justified for you, but it can be done pretty easily
given the right software and hardware tools.

That said, someone here will probably describe a simple method using a
Dremel tool and protractor g.

Mike