On Sat, 29 Nov 2008 13:14:27 -0800, "Bill Noble"
wrote:

just picked up an old bridgeport DRO readout - here's the link
http://cgi.ebay.com/ws/eBayISAPI.dll...m=300277227939

were these things analog LVDT or some other technology - just curious since
I don't have the pickoff assemblies to go with it.

Most use glass scales with optical pickoffs. I think they were
originally developed by Bausch & Lomb in the late 40's and 50's.