HELP!! An Optical Comparator

What is an optical comparator worth?

Help us know more about this Shinko Optical comparator!!!  We have no idea what this is for or its approximate value.  Found newer models from $6K to $40K.  We know its not THAT valuable.  Is it??  You tell us!

Optical Comparator For Sale

The brand is SHINKO #17569, Model# SM-3A, Serial# 4559. A distributor tag on it is Stocker&Yale. It has a 6 ¾ screen, 10x power lens and the X-Y axes is 1.25 inches on the table.

Does anyone know its history?  What was it used for and who would want one from this era?? Tool Shop?? Collector??  Anyone??

 

Stocker&Yale Optical Comparator for sale

The Tool and Die Machine Shop Estate Sale is about to happen and we are getting some great interest in the other tools. But this one stumps us.  Even to know its background would be a great thing to have.

 

 

SHINKO #17569, Model# SM-3A, Serial# 4559