Keilim 13:6-7

Keilim 13:6

The subordinate wood of a metal utensil is susceptible to ritual impurity but the subordinate metal of a wood utensil is insusceptible. For example, if a lock is made of wood and its pins are made of metal –  even if there’s only one – it is susceptible to ritual impurity but if the lock is made of metal and the pins are made of wood, it is insusceptible. [The pins are considered the main part in this example so the lock is subordinate to them.] A metal ring with a coral seal is susceptible to impurity but a coral ring was with a metal seal is insusceptible. The metal tooth on the plate of a lock or the metal tooth of a key is susceptible to impurity on its own.

Keilim 13:7

If hook-poles from Ashkelon were broken but their hooks remained intact, the poles remain susceptible to ritual impurity. Regarding a pitchfork, a winnowing fan, rake and a comb for one’s hair, if one of these utensils lost a tooth and it was replaced by one made of metal, the utensil is susceptible to ritual impurity. Regarding all these cases, Rabbi Yehoshua said “The Scribes have introduced a new innovation for which I have no explanation.”