Mishnayos Keilim Perek 5 Mishnah 1

תנור תחלתו ארבע – an undefined oven is made like a larger pot which lacks a rim at the bottom of the vessel, and they fasten it with plaster on the ground, and the floor of the ground is the bottom of the oven. But even though that of itself it lacks a receptacle, it is nevertheless impure, for the All-Merciful assigned it by its insides, and behold it has an inside.

תחלתו ארבעה – the height of the oven is not less than four handbreadths.

ושייריו – if it was large and it became defiled and afterwards was broken, it would not be purified until there would not be in its remnants four [handbreadths].

במה דברים אמורים – that its beginning and its remnants would be four [handbreadths].

בגדול – that is made to bake and to roast with it in the manner of overs.

אבל בקטן – that is made for young children to play in.

תחלתו כל שהוא – but not exactly any small amount, for less than a handbreadth is not anything (see Talmud Hullin 124a).

ושייריו ברובו – In the Gemara in the chapter: “The Hide and the Grease”/העור והרוטב [Chapter 9 of Tractate Hullin 124a] it raises a question on our Mishnah that is here, that less than a handbreadth, of what is it worth? And it (i.e., the Gemara) answers, that the “remnant” that is referred to is the majority of the large [oven], and it is not about the small over. And We raise the objection, that with a large [oven]. And we raise the objection, regarding a large [oven], surely it states “and its remnants” are four [handbreadths], for it surely teaches: “Under what circumstances?” with a large [oven], implying that the Sages did not dispute with the first Tanna/teacher (i.e., Rabbi Meir) regarding a large [oven] at all. And it answers: This one is speaking about an oven of seven [handbreadths] and that one is [speaking of] an oven of nine [handbreadths], that is to say, something of seven [handbreadths] whose remnants are the majority/larger part, and even though there aren’t four [handbreadths] and there is no oven with less than four [handbreadths], for since, from its outset, it was an important vessel which used its remnants, even though they were not so worthy, and with an oven of nine [handbreadths] where its majority/larger part is a large measure, it defiles with its remnants with four [handbreadths] at its outset.

משתגמר מלאכתו – it refers to the beginning of the oven. From when does the oven become defiled? From when its manufacture is complete.

משיסיקנו (from when he will heat it – sufficiently] – even though that with the rest of earthenware vessels, it is sufficient for them with the smelting of the kiln (as seen at the conclusion of Chapter 4, Mishnah 4 of Tractate Kelim) an oven that requires to attach/glue it with plaster to be interwoven in order to contain its heat, its manufacture is not complete until it can heat sufficiently. But however, it doesn’t require large heating in order to bake bread in it, but rather in order to bake cakes made of spongy dough, dough that its mixture is soft that is made like a sponge and only a small amount of heating is sufficient for it.

משיסיק את החדש כדי לאפות בישן – that the new [oven] in order to bae in it cakes made of spongy dough requires greater heating from the old [oven]. But if the new [oven] was heated with a lesser/smaller heating, that with a heating like this, the old [oven] would be appropriate to bake in it the cakes made of spongy dough, that is when its manufacture is complete. But the Halakha is not according to Rabbi Yehuda.