[ATM] TDE and moving on to # 2

["Russell Jocoy" <russjocoy@hotmail.com>]

   Hello all,

     I have been fighting a turned down edge for about 6 months, (this is a 
part
time fight) and also dealing with redoing the exterior of my home. Of course
the redo of the home takes priority (on the venus side of my relationship)
   To explain further, I started out 2 and a half years ago with a slab of
5/8" plate glass. After cutting two blanks, one 9" and one 10" I generated
about an f5 curve on both surfaces with a diamond blade on a hand rotary 
grinder
mounted on a beam equal to the ROC desired.  All of the steps were 
successful
and I ground both mirrors in tandom through the grits at the same time.
   This was my first attempt at making a telescope mirror, or mirrors..
I used different tools for each piece of glass. For the 9" I used a "washer"
faced tool, and for the 10" I used a tile tool. My choice of tools was to 
experiment the difference in the process. I learned much from this. The 
washer
tool cuts fast but gets real "dirty" fast (from the metals mixing with the
slurry) I don"t know what effect this has on cutting the glass but it was 
quick.
Wets with the washer tool had to be washed much sooner than with the tile 
tool.
    Anyway both mirrors were fine ground down to 5 micron in tandom. This 
was
easy since it was just a matter of changing the glass between grits in
progression.   After polishing the 9" first with a felt sheet streched over
the tool and soaked in CEO , the surface came up quick. I then transfered to
a pitch lap and continued the polishing process.
     Well after many Ronchi tests the TDE rared its ugly head. As I have 
said before I believe it was due to warm pitch polishing in the summer 
inside my garage. "Part time" I have been fighting this dragon on the 
outside of this
thin piece of glass. I know I am making progress but it is sooo slow.
     I am frustrated, and that is an understatement. I now see why all the
advise leans toward "not so thin, not so deep, not so big, if it is your 
first".
That statement sounds like I am telling my son something about women..
     I am putting my 9" on the shelf temporarily in limbo for a period of 
time
to ease my mind and will start polishing the 10" waiting at 5 micron. I 
think
that this will build my spirit back. Once the 10" is polished out enough to
inspect the surface I will see if the TDE was ground in by my process or
polished in by my ignorance. In either case I have a back up to tell a tale.
  Also what I have learned from the process of my first polishing ordeal 
will
shine on the second attempt ( but in my case I don't have to start from the
beginning, I go from polish to polish)  I am rambling on like Davey H. so I
will end, and I will keep all informed on my progress.
         I refuse to give up,  no fire hydrants in my nieghborhood...
                     Keep polishing stupid...... RUSS JOCOY

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