CHECKING A KNIFE
Question: What size nick disqualifies the Mizbe'ach?
Answer: If a fingernail will get caught (if one runs his nail along the Mizbe'ach), this disqualifies it.
Question (Beraisa - R. Shimon bar Yochai): A nick the size of a Tefach disqualifies the Mizbe'ach;
R. Eliezer ben Yakov says, the size of an olive.
Answer: Regarding the plaster, a Tefach or olive sized nick disqualifies. Regarding stones of the Mizbe'ach, a nick that catches a fingernail disqualifies it.
(Rav Huna): If a Shochet does not show his knife to the Chacham to check it, we excommunicate him;
(Rava): We remove him from his job, and announce that the meat he slaughtered is not Kosher.
They do not argue. Rav Huna discusses when the knife was found to be proper, Rava discusses when it was found to be blemished.
(Ravina): If it was found to be blemished, we dirty the meat in the innards, so even a Nochri will not buy it (lest he resell it to a Yisrael who knows that a Yisrael slaughtered it).
A certain Shochet did not show his knife to Rava bar Chinena. Rava bar Chinena excommunicated him, removed him from his job, and announced that the meat he slaughtered is not Kosher.
Rava bar Chinena (to Mar Zutra and Rav Ashi): Look into the matter. He has children to feed!
Rav Ashi checked the knife; it was good. He allowed the Shochet to resume his job.
Mar Zutra: Aren't you concerned for the honor of Rava bar Chinena, who deposed him?
Rav Ashi: He wanted us to reinstate him, if possible!
(Rabah bar Rav Huna): One may slaughter with a detached tooth or fingernail.
Question (Mishnah):... Except for... teeth and a fingernail, for these choke.
Answer: Regarding a tooth, Rabah permitted a single tooth, and the Mishnah disqualifies two teeth;
Regarding a fingernail, Rabah permitted a detached nail, and the Mishnah disqualifies an attached nail.
(Mishnah): If one slaughters with a reaping scythe, and is only Molich, Beis Shamai disqualify, and Beis Hillel are Machshir;
If he smoothed the teeth, it is like a normal knife.
(Gemara - R. Chiya bar Aba): Beis Hillel say only that the Shechitah is not Tamei like a Neveilah, but they admit that the meat may not be eaten.
Support (Rav Ashi): The words of the Mishnah suggest this. It does not say that Beis Shamai and Beis Hillel forbid and permit, rather, that they disqualify and Machshir!
Objection: The wording opposes R. Chiya (bar Aba). According to him, it should say that they are Metamei and Metaher!
Conclusion: Rather, we do not distinguish 'forbid and permit' from 'disqualify and Machshir.' We cannot support or disprove R. Chiya bar Aba from this.
WHERE TO CUT THE KANEH
(Mishnah): If one slaughters in the ring (around the Kaneh), if the entire cut was within the ring, even within a hair's breadth of leaving the ring, it is Kosher;
R. Yosi b'Rebbi Yehudah says, as long as the majority of the ring was cut before the knife left the ring, it is Kosher.
(Gemara - Rav and Shmuel): The Halachah follows R. Yosi b'Rebbi Yehudah. Even he referred only to the top ring, since the top ring fully surrounds the Kaneh;
He does not permit slaughtering (Tosfos - only a majority) within any other ring.
Question (Beraisa - R. Yosi b'Rebbi Yehudah): If one slaughtered in another ring, even though it does not fully surround the Kaneh, since it surrounds the majority, it is Kosher;
Hagramah (the knife left the ring, even after cutting the majority of the Kaneh) is invalid (Shechitah);
R. Chanina ben Antignonus testified that Hagramah is valid.
Answer (Rav Yosef): R. Yosi b'Rebbi Yehudah argues with Chachamim about two matters. Rav and Shmuel rule like him about one (Shechitah in the top ring), and argue about one (Shechitah in other rings).
Question: They said that R. Yosi b'Rebbi Yehudah said his law only regarding the top ring!
Answer: They meant that the Halachah follows him only regarding the top ring, but not regarding other rings.
When R. Zeira came to Eretz Yisrael, he ate animals slaughtered in other rings, which Rav and Shmuel consider to be Hagramah, unlike R. Yosi.
Rabanan: You come from Bavel, where people conduct like Rav and Shmuel! (You should be stringent, like them!)
R. Zeira: Only Rav Yosef says that they disqualified such Hagramah;
Rav Yosef hears from everyone, whether or not he is reliable. He probably erred. Rav and Shmuel never really said this.
Rav Yosef was insulted (when he heard this). 'I don't hear from just anyone. I heard from Rav Yehudah, who is meticulous to record all possible sources of teachings!'
(Rav Yehudah): R. Yirmeyah bar Aba was unsure if he heard from Rav or Shmuel, that three amateurs can permit a blemished Bechor (firstborn male animal) to be slaughtered (outside the Mikdash) if there is no expert Chacham around.
Question: Does R. Zeira hold that a visitor need not adopt the stringencies of his origin and the place he visits?! (Even though he held that Rav and Shmuel permit, he should have been stringent like his origin!)
Answer #1 (Abaye): That applies only to one who travels within Bavel, or within Eretz Yisrael, or goes from Eretz Yisrael to Bavel;
If one goes from Bavel to Eretz Yisrael, since we (in Bavel) are subordinate to them, he conducts in all ways like a resident of Eretz Yisrael.
Answer #2 (Rav Ashi): Even if a resident of Bavel goes to Eretz Yisrael, if he does not intend to return, he adopts all the customs of his new locale;
R. Zeira intended to remain in Eretz Yisrael.
Question (Abaye, of Rav Yosef): Chachamim of Nehardai cite Rav Nachman to say that the Hagramah (which you say that Rav and Shmuel disqualify) is Kosher!
Answer (Rav Yosef): Different regions rule differently.
(Reish Lakish): The top edge of the Kova (a cap on top of the top ring) is Kosher for Shechitah.
R. Yochanan: That is too lenient.
(Rav Papi citing Rava): If the knife Paga (encountered) the Chiti (glands by the Kova) the Shechitah is invalid.
Version #1 (Rashi) Question: Does he mean that the knife cut them, or that it came very close?
(Rav Papa citing Rava): If he left over in the Chiti (cut them anywhere in the middle), the Shechitah is Kosher.
Version #2 (Tosfos) Question: Does he mean that the knife cut through them, or that it cut above them?
(Rav Papa citing Rava): If he left over in the Chiti (cut through them), the Shechitah is Kosher. (Tosfos - had he cut above, it would be invalid. Presumably, this is what Rav Papi meant.) (end of Version #2)
R. Chiya brei d'Rav Avya and Mar Zutra taught like Rav Papa.
(Mar bar Rav Ashi): If he Paga in the Chiti, the Shechitah is Kosher. If he left over in the Chiti, it is invalid.