Re: [ATM] polishing and figuring a 32"

[Ric Rokosz <radicell2@yahoo.com>]

--- Hugues.Laroche@ses-astra.com wrote:

> With my 45" (yeah that is not only big it is
> completely crazy)
> I polished with a 2/3 tool by hand until recently
> (pads, not pitch!).
> Due to the size of my arms (for once I am sorry not
> to be a monkey ;-)
> I could never make COC strokes so all has been done
> with more or
> less off-center strokes. 

 Just to provide some background,I did a 24 inch
cellular of f/3.3 by hand - polish and figure.Doing an
off centre stroke where the edge of the tool does
travel more often near - at - the centre will produce
more wear in that region which if you don't measure
often really over corrects the whole figure.The 24
incher was the first large mirror I did with sub
-diameter tools and was to have been f/4. A 2/3 ratio
tool will readily get you into trouble if you aren't
careful.
> completely polished out
> yet and I plan to continue with a machine, which is
> a different world.

Check out the Zambuto mirror group in the yahoo groups
section for good machine instructions.Plus the
atm_free group for a long discusion on machine work.

I recall John Vogt did his 32 incher with a full size
lap that was cut to work the central area and the edge
at the same time.

Ric



		
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