Re: Grinding elliptical flats

Bob Madden (madden@netcom.com)
Wed, 3 May 1995 22:08:01 -0700 (PDT)

Will you guys help me out? When I asked about testing flats I origonally was thinking about an 8-inch, but diags are also in my interest. I spent the evening reading Texerau, but still dont understand the steps and motions to make a large /or diag flat. Bratislav or Mel or any one out there could you post the necessary steps, eg, what do you grind against, material, strokes, what ever? Whooee, am I ready to learn. I reeally do wana make a big flat -

Bob, whoops, friendly Bob that is

):-{])) <---- madden@netcom.com madden@svpal.org Remember amateur astronomers: "keep looking for the next Universe"

On Wed, 3 May 1995, Dean Ketelsen wrote:

> My experience in making elliptical flats is that it is easier to make
> several at once, blocking them to a flat tool with pitch, rather than
> make them one at a time. For instance, if you are making 1.5 inch
> diagonals, you could probably make 5 or 7 at the same time blocked
> to a 6" tool with pitch. Then you can test the whole bunch at once
> with a 6" reference flat under a monochromatic light, or even a
> flourescent lamp. Make sure you maintain a bevel on all of them as a
> chip flaking off can scratch the whole block! Good luck.
>
> -Dean
>