I'd never heard of Duro (too young, I guess ) but a Google search turned up some interesting information about tools made by the [Duro Metal Product Co.] on the Old Woodworking Machines website (http://www.owwm.com). I couldn't find a manual for the overarm router, but the Photo Index on that page has a couple of entries for 3100 / 3101 overarm routers. If either of those appears to be similar to your unit, you can apparently send a message to the owner like so:
Originally Posted by Bill Garcia
* Click on the Serial Number link for the machine you're interested inGood Luck!
* On the next page, click on the Submitted By link
* On the next page, click the Send Message link
* Finally, fill out the form and send your message