Knife, pippin and auriform files are machinist’s files characterised by a thin ‘knife’ edge.
The extremely acute angle of this ‘blade’ makes these files very versatile tools. They can be used to smooth and deburr tighter internal corners than three square files.
What are the characteristics of knife, pippin and auriform files?
Cross section
Knife files have a wedge-shaped cross section.
They are easily identified, because they look like knives!
Pippin files have similar cross sections to knife files, but the face opposite the knife edge is rounded and double cut.
Due to the shape of their cross section, these files are also known as apple seed files.
Knife and pippin files can be used to create narrow v-shaped grooves and slots.
Pippin files can also be used to create the rounded notches in a key that allow it to open a lock.