Hammered by master craftsmen, appreciated by connoisseurs: Until the early 20th century, the teeth of rasps were hammered into the unhardened rasp body exclusively by hand (using a pointed chisel and hammer). The slight variations in the depth and spacing of the individual teeth result in a slightly inhomogeneous texture of the working surface. This results in smoother cutting behaviour with fibrous material such as wood. There is no "chattering", which is why experts still favour the "hand-hammered" rasps today.
