My "new" router plane

This is the router plane that got me interested in patent searching. The thumbscrew is marked Pat June 9, 1925 on one side and Economy on the other. I believe that the thumbscew is patent 1,541,518 Thumb or wing screw. This patent has also been entered into Datamp (Directory of American Tool and Machinery Patents). My post about it in a woodworking forum is here. It was my first foray into the uspto's classification system and was also the first time I fooled on the hunt. I had mistakenly assumed the patent was for some feature of the tool, not for the thumbscrew itself! Tools and thumbscrews are understandably classified differently so I did not find the patent in the classifications I was perusing. It wasn't until I resorted to a brute force search (looking at nearly all 1,119 utility patents issued on June 9, 1925 in the early dial-up day of the internet) that I found the patent.