The 31 wrench came with Hart Carter threshing machine self feeders. These feeders were optional equipment that could be ordered with the threshing machines. Several threshing machine companies including John Deere offered the Hart Carter Self Feeders and the parts and 31 wrench are shown in their threshing machine parts lists.
Nichols & Shepard / Oliver threshing machines and combines listed the same wrench but marked with the part number F2-0005
The R43 tee handled socket wrench is another self feeder wrench. It showns up in Advance-Rumely Threshing Machine Parts Lists for feeders that were originally made by the Ruth Self Feeder Co. of Halstead, Kansas (my hometown). Ruth was acquired by the Parsons Self Feeder Co. of Newton, Iowa around 1901 and in turn were eventually acquired by the Maytag Company. The Maytag Company continued to sell the Ruth Feeders for several years.
The mark you think might be a "10" is probably a casting identification mark.
