Kelim, Chapter Twelve, Mishnah Five
1) A nail which he adapted to be able to open or to shut a lock is susceptible to impurity.
2) But one used for guarding is clean.
3) A nail which he adapted to open a jar:
a) Rabbi Akiva says that it is susceptible to impurity,
b) But the sages say that it is clean unless he forges it.
4) A money-changer’s nail is clean,
a) But Rabbi Zadok says: it is susceptible to impurity.
5) There are three things which Rabbi Zadok holds to be susceptible to impurity and the sages hold clean:
a) The nail of a money-changer,
b) The chest of a grist-dealer
c) And the nail of a sundial.
d) Rabbi Zadok rules that these are susceptible to impurity and the sages rule that they are clean.
Section one: A nail which one bent to be able to open or close a lock is considered to be a vessel and it is susceptible to impurity.
Section two: However, a nail that is simply stuck in a door to close it and keep out cats or other animals is not sophisticated enough to be a vessel and it is clean.
Section three: According to Rabbi Akiva, if he bends the nail to be able to open up a jar, it is already susceptible to impurity. The other sages say that to turn a simple nail into a jar opener he must forge it again in the oven. It is not susceptible until he does so.
Section four: The Rambam explains that the money-changer uses his nail to hang up his scale. Another possible explanation is that this nail was used in the daily set up of the money changers “table” (in Hebrew the money-changer is called “the table-man”). According to Rabbi Zadok this nail is a vessel and is susceptible, whereas the sages disagree.
Section five: This section and mishnah six were brought to Mishnah Kelim from Mishnah Eduyot 3:8-9. In the case of Rabbi Zadok, this section merely repeats that which we learned in the previous two mishnayot. It is interesting to note the different literary styles between the regular tractate, Kelim, which organizes its material by topic, and Eduyot, which organizes its material by name.