In article 1129169527.854573.124070
@g49g2000cwa.googlegroups.com,
says...
I snagged one on ebay for $75, new condition, a while back...darn thing
is one of the most useful things I have ever paid for. All I can say
is it's like when someone told me "If you use your Bridgeport a lot,
get a DRO"...I did, and they were 100% right, makes working on projects
boatloads more enjoyable...same can be said for the centering
scope...keep an eye open on ebay, if you take your time, they pop up
every two weeks or so...don't pay more than $100 ish though...mine is
a ECCO, very nice :-)

Just goes to show we've all got our own ways of working. I
had a very nice SIP (the Swiss jig borer folks) centering
scope that sat on the shelf for about 20 years before I
sold it on ebay. I never used it, and though I was afraid
I'd have a need for it as soon as it was gone, haven't
missed it a bit.

On the other hand, I have a couple microscopes that I use
all the time on the mill. One is a small inspection
microscope with a calibrated filar eyepiece that's handy
for making measurements in place that would otherwise
require moving the part to a toolmaker's microscope. The
other is a long focal length microscope (or maybe it's more
properly a telescope) that allows you to get a magnified
view in places where you can't comfortably place your head.
Both can be mounted on a mag base.

Ned Simmons