> on Ellison wrote:
>
> >Can't find one but I think I have demonstrated the principle
> >well enough.
>
> So it has not been demonstrated to work on a mirror-like
> polished surface as previously described.......
>
> >You seem to be suggesting that this method used on a
> >transparent/translucent surface
>
> You forgot to mention it's a mirror-like polished surface
> again...............
>
> Just how large of an area was being testing anyway?
>
> >Anyway Dunn also used the feeler gauge method which has
> nothing
> >to do with light, because he had a set of five dollar
> "feelers"
> >in his pocket.
>
> Ya can't wait until he re-does his "diamond can barely scratch
> granite" claim with a better than dull diamond scriber this
> time and amazingly gets the same result as the last
> time...............



Just tried the straight edge on a chromium mirror vs. an opaque surface, the back of the same mirror.
Anyone doubting this can do it themselves, pocket mirror and steel ruler.

The reflective surface gives an indication that the gap is slightly greater. NOT less.

Engineers have to deal with surfaces of varying reflectance.
Dunn is amply experienced enough to take this into account.

So therefore if what you say it true and the stone is translucent/reflective his measurements of planar deviation would be greater, not less.
If Dunn had only used the light and straight edge method his measurements would be over/greater. Not under/less.
In other words the surfaces would be even more accurate than Dunn claims.
Fortunately Dunn used other methods to corroborate.
Therefore unless he is lying. At present we have to accept his measurements.

A normal machine shop approach would be to identify undulations using the light and straight edge method. Once the areas are identified, either a DTI or feeler gauges would then be used. Which is exactly what Dunn did. He's a trained and experienced engineer
Coarse and fine measurement.



I don't know what your last paragraph means .