ATM 3 inch reflector

[jsgrmfg@gracemfg.com]

A few years ago I shaved down an elliptical diagonal
for exactly the same reason that you have in mind -
to make a 3" reflector.  I did it more or less as described in one
of my TM books, but I don't remember which one.  Anyway,
I protected the aluminized surface with masking tape,
embedded the taped mirror in plaster at a 45 degree angle,
made a "hole saw" out of a piece of steel conduit with
an I.D. that matched the desired minor axis and, at low speed
on my drill press, chewed through the whole thing using
lots of water and 180 carbo.  It was slow, it was messy and it
made awful noises, but the end result wasn't bad at all.  Just
a tad of roughness around the edge of the shiny side easily
smoothed away with a carbo stone.

Jim Sturtevant