This tool was found in a box of wood planes from a farm. It is "reversible" in that the arms can rotate 180 degrees. The pivot has a narrow profile (1/8") on one side and a wider (3/8") on the other. The inside of both arms are textured with small points as if to hold something firmly. About 6" long total height. The numbers 50 on one side and 60 on the other can be read. Any ideas?

