Do you have one? I do. It is such a wonderful little machine with a simple, yet effective purpose.
Made by the Singer Manufacturing Company in the 1930’s it was marketed as an aide to the fashion sewer. It was designed to finish the edges of seams and help reduce bulk when using something like wool. The machine cuts a wave in the fabric and is faster and easier to use than the hand held scissors designed to do the same thing. Pinking the edge also helps reduce the chance of the seam fraying.
The cut is not based on the blade being sharp, but rather the pressure of the blade on the steel disk. If the pressure of the blade on that disk is increased, it can cut through thicker fabrics, including leather. There is also a built in cutting guide on the side of the machine. The machine is best secured to a table or other such surface with a C-clamp to stop it from moving around when using it. A clamp came with the pinker when it was new, but these have often been lost over time. A new clamp works just as well.
The machine came with the wide-wave blade but by special order other blades could be obtained. These blades were a straight edge blade and a narrow scallop blade. As these were a special order, they are much harder to find today.