פירוש על כלים 13:6

הפין (bit of a key) – the teeth of a key with which they open the door. And this form of this key is known in the Egyptian kingdom and throughout the land of Israel.

Introduction Our principle teaches and illustrates the general principle that a vessel is considered to be made of the material which makes up its function part. This principle is of importance because the rules governing wooden and metal vessels are different.

אפילו אחת טמאה – and even though that the teeth on their own without a lock are ritually pure, they (i.e., the Sages) established it that with a lock they are ritually impure , nevertheless the teeth are considered as essential and the lock serves [the teeth].

Wood that serves a metal vessel is susceptible to impurity, but metal that serves a wooden vessel is clean. If the functional part of a vessel is made of metal, it is susceptible to impurity even if its ancillary parts are made of wood. But if the functional part is made of wood, it is not susceptible even if its ancillary parts are metal.

אלמוג (coral- a species of cedar tree) – KORALI in the foreign language, and it grows in the depth of the sea. And its beginning is soft prior to the air making it float/become thick and they open with it something sealed. And in Scripture, it is עצי אלמוגים (I Kings 10:11): “[Moreover, Hiram’s fleet, which carried gold from Ophir, brought in from Ophir a huge quanity] of almog wood/sandalwood [and precious stones].”

How so? If a lock is of wood and its clutches are of metal, even if only one of them is so, it is susceptible to impurity, but if the lock is of metal and its clutches are of wood, it is clean. The mishnah now illustrates this through several examples. The first example is a lock. The clutches are the functional part. Therefore, even if only one of them is of metal, the lock is susceptible.

השן שבטס (the key-ward fastened to a thin plate) – it is not similar to the bit of a key of that which opens for the tooth is used on its own, what is not the case with the bit of the key. Therefore, it is ritually impure on its own.

If a ring was of metal and its seal of coral, it is susceptible to impurity, but if the ring was of coral and its seal of metal, it is clean. The main part of the ring is the ring itself. Therefore if it is of coral, the ring is clean (coral is never susceptible to impurity), but if it is of metal, it is susceptible.

The tooth in the plate of a lock or in a key is susceptible to impurity by itself. Since the mishnah discussed locks, it adds that if the tooth in the plate of a lock is separate from the lock or key, it can still be susceptible to impurity, because it is considered a vessel in and of itself.