I know that tool as a face float, Tony.
It really is generally just created on a straight manage, but that bent file type was generally a metalworking version.
I am attempting to obtain hyperlinks to show, but they are a bit hit or miss. Benchhand joiners, carpenters and the like utilized them to get into awkward slots and tight spaces. Mortices and the like, or musical instrument makers.
In some cases referred to as a cranked rasp if it really is genuinely coarse, iirc.
It really is the type of tool that only a person who performs with wood everyday would purchase. It really is a very good point, extremely helpful in just the appropriate scenario, but most people would not assume to purchase a single or have need to have of it.