this post is a duplicate of one on OC, but taking the liberty of posting here also for the non-adventuresome
- original thread .
HERE
(and I'm hoping to get N8 involved, hello N8 . . . )
(and perhaps even a JoeK - JoeC 'contest' ?, more at the end of the post)
this is all about flatness
a bit of explanation: I bought a "Flatscope" which is an optical flat built into a reflex viewer with a mercury lamp and a green filter
- as such each visible fringe = 0.000010749" (~ 0.000273mm) and 'measurement' is made counting the fringes, or fractions, in terms of their deviation from linearity
(its not about how many fringes, its how curved they are; a bit oversimplified but that's the gist of it)
so I started looking at wbs, my present interest
(note that the surface must be reflective, more on this later; and that the images are severely pushed to enhance the contrast)
some examples - of my handicraft, no blame to the mfgrs here
the first wb bp I looked at, I was shocked (not my lapping)
a 'not good' of mine
here the die area can be seen towards the lower center
and one that is actually pretty good
too many images I’m told, have to split the post
to be continued . . .