On Sun, 25 Nov 2012 19:35:01 -0600, "Pete C." wrote:

I suspect that in the olden days such a slot would be cut with a chisel
(not a wood chisel), also suspect that would still work today...

You suspect correctly. The end slots which were already existing in the
original cast molds (my mold is a weldment of cast pieces) were modified using
the same 'router as mill' technique and the *much* smaller remaining triangles
were removed with a long, very sharp, cold chisel.

http://www.mysecondbathouse.com/smal...versedraft.jpg
Or the whole page if anyone wants to see it,
http://www.mysecondbathouse.com/firstmold.html

Searching for a faster way...
--
William