Measuring internal diameters

[routercnc]

Now that I have my lathe I am looking into tools for accurately measuring internal diameters e.g. to press fit bearings into pockets.

I'm looking for something better than the digital calipers I have (which are not that accurate in general).

I've seen this type used (an analogue internal micrometer) ~£60:
http://www.ebay.co.uk/itm/5-30mm-Moo...-/231227465653

This quotes a resolution of 0.01 mm but no accuracy value. Could be good enough?

The digital versions are pricey ~£190:
http://www.machine-dro.co.uk/5-30mm-...80-series.html


There are telescopic bore gauges, but have never used them and there seems to be a knack to using them. How do people find these? I have an external micrometer so could mic off the gauge assuming the gauges give repeatable results:


Anyone using anything else? thanks