Keilim, Chapter 14, Mishnah 3. The subject of this whole chapter is implements of metal, and the question it keeps returning to is when such an implement has reached the status of a finished keli that tumah can attach to, and when it falls short: because it is unfinished, because it functions merely as an accessory to some other object, or because it has been fixed into the ground. Our mishnah surveys one workman's tool and household article after another, and behind every ruling stands a single quiet question: does this object stand on its own as a keli, or is it no more than an appendage of something else?
A builder's bar and a carpenter's spike
The mishnah begins: "hachantar shel banai", the iron bar with which builders would break through a wall, "vehadakor shel charash", the spike a carpenter uses to bore holes in wood. Of both the mishnah rules "harei eilu temei'in", they are susceptible to tumah. Each of these tools is fitted into a wooden handle, yet the wood does not weaken their status. What does the work, and what gives the tool its identity, is the metal, and so the tool is treated as a metal keli that can become tamei.
Pegs driven into the earth
Next: "yitdot ohalim", the pegs used to pitch a tent by holding down its ropes, "veyitdot hamashochot", the pegs of the land surveyors. Surveyors would hammer pegs into the ground and stretch cords between them in order to take the true measure of a field, to know how far it reached and how large it was. Of these pegs too the mishnah says "temei'ot", they can become tamei.
The question here is not the metal but the ground. Normally an object joined to the earth is regarded as part of the earth and is therefore tahor. A peg, however, is not called mechubar lakarka. It was never meant to stay where it was driven; it is put in precisely in order to be pulled out again, and an implement that is only temporarily lodged in the soil keeps its own independent standing as a keli.
Two kinds of chain
"Shalshelet shel mashochot temei'ah", the surveyors' measuring chain is susceptible to tumah. Here again one might have thought otherwise, since the chain is fastened to pegs planted in the earth, but as with the pegs themselves the arrangement is temporary and the chain will be taken up when the measuring is done.
Against this the mishnah sets "ha'asuyah le'eitzim tehorah", a chain made for wood, that is, one used for binding bundles of wood together or for taking their measure, is tahor. This chain has no name of its own. It is not called by any independent title but is regarded as belonging to the wood it serves, made for the wood and part of the wood. An object with no identity of its own is not susceptible to tumah.
The chain of a bucket
The mishnah now supplies measurements: "shalshelet deli gadol", a big bucket's chain, is susceptible for "arba'ah tefachim", four tefachim, while "veshel katan asarah", the chain belonging to a small one, is susceptible for ten. Two ideas work together here. Considered by itself, such a chain carries no title at all: it is tafel, an accessory to the bucket. Yet since it is fastened on, the bucket's tumah reaches it, because the chain functions as a yad, the handle through which the vessel is put to use. Only the stretch that genuinely serves as a grip is included, and how long that stretch is depends on which bucket we are speaking about.
A big bucket full of water is a heavy load, and nobody hoists such a weight while holding a long span of chain. Someone hauling water up in a big bucket will therefore grip the chain close in, no more than four tefachim above it, and precisely those four tefachim count as the handle. A small bucket weighs little, and its user may take hold of the chain anywhere up to ten tefachim, so ten tefachim constitute its yad. Whatever measure qualifies as the grip carries the status of the bucket itself and contracts tumah along with it, while the remaining length, for which the one drawing water has no need, lies outside.
The blacksmith's stand
"Chamor shel napachim tamei", the blacksmith's donkey, meaning his stand, is susceptible to tumah. A smith heats metal in his furnace until it grows soft, and to keep the coals blazing he pumps a bellows that forces air into the flames. The support on which that bellows sits, the piece against which he props his elbows while he labors, has the standing of an independent keli, and when it is made of metal tumah can attach to it.
A saw fixed above a doorway
The mishnah turns to a saw, "megerah". A man fastened one to the beam above a doorway with the teeth pointing downward, so that they jutted into the space of the entrance, and he could then push and pull planks against the beam in order to cut them. With the teeth sitting "betoch hachor", inside the opening, the ruling is "temei'ah": tumah still reaches the saw. One might have argued otherwise, since the saw is now attached to the building, and whatever is attached to a structure is ordinarily counted as part of the ground and tahor. But the man changed nothing in the saw itself; it retains its character as a portable vessel, and a portable vessel is susceptible.
"Asah milmatah lema'alah tehorah." If, however, he fixed the saw the other way round, so that its teeth are buried inside the beam and do not protrude into the doorway, it is tahor. Now the teeth have become part of the beam; the saw is regarded as joined to the ground, and it can no longer receive tumah.
Covers of vessels
The final clause: "vechol hakisuyin tehorin", every one of the metal lids is tahor, "chutz mishel meicham", apart from the lid of a heating urn. A lid does not share the status of the vessel it seals. It is a distinct object, and on its own it does not qualify as a keli, so tumah has nothing to attach to. The exception is the meicham's cover, which is itself serviceable as a vessel; once a lid amounts to a functioning keli on its own terms, it becomes susceptible just like any other.
Read as a whole, the mishnah teaches one principle in many forms. Metal in the service of work becomes a keli that tumah can reach; a bar, a spike, a peg pulled up again, a chain that is a handle, a smith's stand, a saw that was never itself altered. But whatever has no name of its own, whatever is swallowed up into the wood it binds, into the beam it was sunk into, or into the vessel it merely closes, stands outside the reach of tumah altogether.