I wish I could remember more about it, but in the late '60s the art and
framing store where I worked had a hand cranked machine to cut oval
matts for photographs.  You set the settings for the size of the matt,
and began cranking.  Not only did it cut the precise oval needed, but
made that cut at a 45 degree angle, like any other matt.  It was a real
mechanical marvel. 

Mike in Woodland