On Fri, 14 Nov 2003 12:03:37 -0500, "surftom"
wrote:

How do I *accurately* (n.nnnn) measure very small hole diameters?

I can poke them with a numbered drill but that would only get me close by
"feel" and only if the hole was a standard size. e.g. measureing a .0431
hole is kind of hard with a vernier or mic

No real reason - enquiring minds just want to know

There are devices that look rather like a large jeweller's loup that
are used to measure things like that. They often have interchangable
reticles gradiated in millimeters or thousanths of an inch etc. They
are called "optical comparators" and "scale loups"