Kelim, Chapter Thirteen, Mishnah Three
1) A harhur that is damaged is still susceptible to impurity until its greater part is removed.
a) But if its shaft-socket is broken it is clean.
2) A hatchet whose cutting edge is lost remains susceptible to impurity on account of its splitting edge.
a) If its splitting edge is lost it remains susceptible on account of its cutting edge.
b) If its shaft-socket is broken it is clean.
Section one: A harhur is the iron vessel into which an ox-goad (see 9:7) can be placed in order to dig and to remove dirt from a plow. It is susceptible to impurity even if damaged, as long as its shaft-socket, the opening into which the ox-goad is placed, is intact.
Section two: The head of the hatchet has a thin side for cutting and a thick side for splitting wood. If either side remains usable, it is still susceptible.
If the shaft-socket, the hole into which the head is affixed, is broken, the entire hatchet is unusable and it is pure.