פירוש על כלים 5:11

של אבן ושל מתכת טהור – [an oven] that is of stone is completely pure, and that of metal is pure from the law of an earthenware vessel, which does not defile from its airspace, and it has purity.

An oven of stone or of metal is clean, But the latter is unclean as a metal vessel. All stone vessels are totally unsusceptible to impurity, so a stone oven can never become impure. A metal oven can become impure but not in the same way as an earthenware oven. While an earthenware oven is susceptible to impurity through its interior space, and not from its outside, the reverse is true for a metal oven. Also, a metal oven that has been attached to the ground is not susceptible, whereas an earthenware oven is.

וטמא משום כלי מתכות – that it becomes susceptible to receive defilement from its outside and becomes a primary source of ritual impurity. But if it is attached to the ground, it does not defile, for all that is attached to the ground, behold it is like the ground, except for an oven and a portable stove on feet with caves for two pots which are of earthenware, as it is written concerning them (Leviticus 11:35): “[Everything on which the carcass of any of them falls shall be unclean:] an oven or stove shall be smashed,” that which has breaking up/cutting out.

If a hole was made in it, or if it was damaged or cracked, and he lined it with plaster or with a rim of clay, it is unclean. What must be the size of the hole [for it to be pure]? It must be big enough for the flame to come through. If the oven was in some way damaged such that a flame could go through the hole in the side, the oven is pure because it is not usable. However, it becomes susceptible again to impurity once it has been repaired.

ניקב נפגם נסדק – and he made a treatment of plaster to close up the perforation or the damage or the crack. Or he made at its mouth a supplement of plaster, it is impure, like the law of an earthenware oven.

The same applies also to a stove. A stove of stone or of metal is clean. But the latter is unclean as a metal vessel. If a hole was made in it or if it was damaged or cracked but was provided with props it is unclean. The same general rules apply to a stove. The mishnah adds that if he makes "props" which is either a tripod for pots put on top of the stove or legs to plug the holes on the bottom, the stove is again susceptible because it is usable. As usual, once a vessel has been repaired, it is susceptible to impurity.

וכן בכירה – and similarly, the measurement of a perforation of a portable stove on feet with caves for two pots, in order that the flame can exude through it, like the measurement of the earthenware oven.

If it was lined with clay, whether inside or outside, it remains clean. Rabbi Judah says: if [the lining was] inside it is unclean but if outside it remains clean. According to the first opinion, if he spread a clay lining over a stone or metal stove, it is still pure, meaning it is not considered an earthenware vessel. This is because the clay is not necessary and does not affect the functioning of the oven. Rabbi Judah holds that if the clay lining is spread inside the oven it does make the stove into an "earthenware vessel" and subject to the purity rules governing such a vessel. But if he spreads it on the outside of the vessel, it is still considered to be of stone/metal and the rules governing an earthenware vessel do not apply.

ועשה לה פטפוטין (if he made legs for the stove – so that it no longer rests immediately on the ground) – here it does not teach: “that he made for it plaster/paste” [because] they don’t make plaster/paste for a portable stove on feet with caves for two pots that was perforated, damaged or cracked like they do for an oven, but rather, when it was perforated or damaged, the portable stove on feet with caves for two pots is in the place of the perforation to make legs for the stove, they are the legs of the portable stove on feet with caves for two pots, like TRIPID in the foreign language, that the portable stove on feet with caves for two pots sits on these legs for the stove.

מרחה בטיט – [if he spread plaster over it] it is pure, for the spreading/smearing of plaster on it, has no effect other than with an oven that they bread read inside it, but not with a portable stove on feet with caves for two pots, because they don’t bake or cook within this portable stove on feet with caves for two pots itself, but they leave it it within it or on top of the pot. But the Halakha is not according to Rabbi Yehuda.