re: more box ways

Thanks to ballendo and George for the detailed enough answer to my vague
questions.

There are two machine tools in particular that seems most magical to me. One
does what they call deterministic microgrinding. The idea here is that with
a stiff enough machine and a relatively coarse grit diamond grinding tool, a
surface can be produced on glass or ceramic that is essentially polished
with a very high form accuracy of a few nm.
The other is the diamond turning lathe, which turns an aluminum or nickel
surface also to a few nm finish and 10's of nm accuracy.
There was quite a bit of open literature on this subject while these things
were in development a few years ago, now that the machines work they don't
seem to be writing much about how they work.

I have long wondering if there was any overlap between their mechanics and
more conventional CNC machines.

For example, a calculation was presented showing the limit in accuracy
caused by the limited thermal conductivity of and high thermal expansion of
turcite/teflon. It was small but signficant on the nm scale for certain
cutting profiles.

Of course ways are only 1/3 the problem with these machines, spindles are
another third, positioning and feedback the third.

Elliot Burke