types of saw fences.  It is important that a tall fence be square 
to the table, or different height work will register differently; 
and come out different widths.  For some work such as some dadoes 
and some angles it is handy to be able to swivel the blade and cut 
into the fence slightly.   A wooden fence such as waxed hard maple
accomodates this, and is also relatively easy to keep in shape
(flat and straight).  The aluminum extrusion fence on the saw in front
has some interesting adjustments.  It can be slid forward or back on
the saw.  It can also be turned and refitted so the flat side is down
to the table, and the height of the fence is its thickness.  This 
extrusion is not flat, enough to be a problem.  I'm trying to come up
with a reasonable solution.  Ideally, i would like to machine a ductile
iron replacement a little bit thicker than the extrusion.  But that is
probably not realistic since the length (~48") is much greater than 
the travels on my available machine tools.