Re: [ATM] figure stroke ten inch

[Mike Lockwood <melockwo@uiuc.edu>]

Tom,

Tom Fredrickson wrote:
> I have made a new lap with softer pitch and the figure is very good.
> I now have a problem with surface roughness. Could this be caused by
> the fresh lap? It is so bad that it distorts the lines when doing a
> ronchi test. My plan is to mix up some fresh cerox and just spend some
> time polishing. Should I use COC stroke work back toward a sphere?

Usually softer pitch leads to less surface roughness, because the 
pitch conforms more quickly to the aspheric mirror surface.  So, 
something is not right.  Are you using lots of polishing force, or is 
the lap not entirely in contact?  Does the lap/mirror slip and grab 
during polishing, or is the drag consistent and smooth?

Yes, if you have made the mirror as rough as it sounds, you should 
smooth it out a bit.

	Mike Lockwood

_______________________________________________
ATM mailing list http://www.atmlist.net/