Spoon bits are relatively rare bits, and tend to be forged by hand rather than mass produced.
The spoon section of the bit is moulded in a die to create the characteristic spoon shape. As these bits are forged from steel rods, there is no need to change the main part of the shank. Only the tip of the shank needs to be a different shape to allow the tool to fit into either a hand brace or a drill press or lathe.
The edges are then carefully ground to an inward bevel with a slip stone to create a sharp edge around the outside of the spoon section..
A slip stone is a sharpening stone that has a rough surface. Slip stones can come with different grit numbers: in this case, a fine stone, which has a high grit number, is used.