Here is the page for the National Brand of shop Microscopes we have several of these in use and the only problem has been the light sources. I just talked to one of the groups that uses this type scope about using one of the new LED small flashlights as a light source.
If you go with a National shop around as the scope is heavily discounted.

http://nationaloptical.com/products/shop/models/186.html

Here is a new one to me, look like a good price.

http://www.microscope.com/omano-shop-microscope-p-316.html


I have used several of this type 30X and the 50X model from Titan and as always the light source is the problem.

http://www.titantoolsupply.com/catalog.asp?prodid=522579

I checked with the shop about the light source for tube scopes and was told the only way to go was with LED's. It was also noted that they have brought several of the stereo zoom scopes to the shop floor since the production area has been downsized. These scopes have a pretty good depth of field a nice thing to have while looking at an edge.  

Have a look at this site, they have a couple of versions that may work for you.  Their prices are "Made in USA" as well.

http://www.ptc1.com/public/optical232.htm

 

I Have a very good Panisonic 100X "Light Scope FF-394E", used to have a 30 or 50X as well.

They are a great scope

I am looking for an equivalent to the 30X FF-393E which has been discontinued.   

Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.    

I also recently found out that the FF-393 and FF-394 have been discontinued.  Hope the ones we have will hold out until something comparable in quality, even at a somewhat higher price, is available. It is hard to sell the bean counters why you have to spend several times the money for a replacement.