RE: [ATM] Next moves

["Oliver Kersten" <oeli@comesso.de>]

Hi,

thank you for your analysis.

I'll try to produce some readings the next days. By now I thought that it is a
little bit early for that.

I don't use a machine, just my hands.

The lap is slightly sub-diameter (about 9.5 "), with 7 facets in each
row/column (not hex shaped). The pattern is asymmetric according to the
mirror's center. The lap was used now for maybe 3 or 4 hours. I put a thin
layer of fresh pitch on the facets about 2 hours ago. So I don't think it is
finished. I normally do half an hour of cold-pressing before polishing. The
lap lies on a kind of thin carpet for polishing.

I rotate the base (mirror when TOT, lap when MOT) every 4 or 5 strokes for
about 30-45 degrees (no strong pattern). The upper part is rotated after every
stroke maybe 10 degrees.

I cannot see any fractures on/in the glass. Only what we call "Schlieren" in
German (the structures inside). Haven't found a word for that in any
dictionary.

Some of the irregularities are clearly caused by the turbulences while taking
the photos ...

Thanks,
  Oliver

Jerry:
> Dang! I forgot to mention that it looks to me like I can see your pitch lap
> in the glass. If it is full sized it looks like you have about 9 or 10 rows
> of small facets with maybe too much space between them. Probably they are
> hex shaped. Hex lap mold? I've had hex laps put stark hex patterns in
> mirrors. I haven't seen squares on mirrors polished with square facets.
> Besides trimming difficulty that is another reason I don't like hex facets.
> Or you are working some multiple of 3 positions (like 3, 6 or 12)in the walk
> around the barrel.  And I guess I should mention that it is possible that
> your are canceling the relative rotation of the disks by stepping around the
> barrel in one direction while rotating the disk in hand the other direction
> by the same amount. Another scenario with much the same effect is to step
> too far around the barrel and to rotate the disk in hand too far resulting
> in a 180 degree relative rotation between disks. If by machine it would be
> table rotation and stroke speeds repetitive "to a fault" so to speak. I
> don't think it would be a cellular blank print-though for a 10" mirror would
> it?
>
> I know what you are thinking.... you think I've been into the cerebral oxide
> again.
>
> Jerry
>
>
>
>
> -----Original Message-----
> From: Oliver Kersten
>
> Hi all,
>
> I'm still fighting a TDE on my 10" F5.5 and try to reach a sphere. I've put
> my
> latest Foucault images under
>
> http://www.comesso.de/oeli/atm/mirror/mirror.html
>
> I think the shape gets better, but very very slowly.
> Once again, I would like to ask for any suggestions for my next moves...
>
> Greetings, Oliver
>
>
>
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>
>
>
>

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