In posts #22 through #36 on this thread there is a discussion on those sockets we sometimes find in a vintage 1930's or 1940's socket set that seem to have a hundred "points" instead of 6 or 8 or 12 in the service opening, called "internal knurling" by Walden and Husky, used on radio and similar cabinets with knurled head screws. Also discussed are the spinner versions. This morning I found this L-wrench at my flea market. No branding or marking of any kind, but it sure looks like it may have been made for the same purpose.