The metal shaper is a derivative of the planer, which is ultimately a machine meant to replace a human with a chisel forming metal. I use an Atlas shaper. I don’t use it all that often but for jobs such as removing mill scale from a large piece of Hot Rolled steel, the shaper will do it without ruining a good end mill and it produces a great surface finish.
The Shaper is a tool with a “ram” that moves back and forth in the y-axis (depending on your point of reference) and holds a single point cutting tool akin to a lathe toolbit or chisel. The table is adjustable in the x and z axis and usually has a power feed provision, so that for each stroke of the ram across the work the table then moves incrementally over so that a surface can be flattened. The shaper is one of the few tools that allows internal keyways and other features to be machined, including polygonal holes, given the proper setup.