GEMARA

11a - Mishnah: The general rule is, one may use for Sechach only something which grows from the ground and is not Mekabel Tum'ah.

12b - Rav Yehudah: 'Male' arrow shafts are Kosher for Sechach (they are inserted into the arrowhead). 'Female' shafts (they have a hole to hold the arrowhead) are Pasul.

Question: Obviously male shafts are Kosher (they are not Mekabel Tum'ah, for they are Peshutei Klei Etz (Kelim from vegetation that do not hold anything)!

Answer: One might have thought that we decree to forbid male shafts lest one use female shafts. Rav Yehudah teaches that we do not.

Question: Obviously female shafts are Pasul (they are Mekabel Tum'ah, for they have a receptacle)!

Answer: One might have thought that they are not Mekabel Tum'ah, because their receptacle is made to be permanently filled. Rav Yehudah teaches that we do not say so.

15a - Question: Why do R. Yehudah and R. Meir argue about Gezeiras Tikrah in two Mishnayos (14a and 15a)?

Answer #1 (R. Chiya bar Aba): The Mishnah of 14a discusses smooth boards. They argue about whether or not we decree lest one use Kelim for Sechach.

Question: Rav Yehudah allows male shafts for Sechach. He does not decree lest one use female shafts. Similarly, he would not forbid smooth boards lest one use Kelim!

Answer #2: We must say that they argue about Gezeiras Tikrah in both Mishnayos.

16a - Rav Ami bar Tivyomi: If one used worn out Kelim for Sechach, it is Pasul.

Abaye: This refers to rags less than three by three (fingers). They are not useful for rich or poor people.

Support (Beraisa): One may not use for Sechach the remnants of a mat of rush or reeds, even if it is less than the Shi'ur (for Tum'ah).

Bava Basra 66a: R. Eliezer is Metaher a baker's board attached to a wall because Tum'ah of wooden Kelim without a receptacle is only mid'Rabanan.

RISHONIM

The Rif and Rosh (1:21,24) bring the Mishnah and Rav Yehudah's law and the question and answer about female shafts.

Ba'al ha'Ma'or (6b DH v'Ha): R. Chiya bar Aba argues with Rav Yehudah. R. Chiya says that Tana'im argue about whether or not we decree lest one use Kelim for Sechach. Nevertheless, since the Halachah follows R. Yehudah, even R. Chiya permits male shafts. Therefore, the Rif brought the Halachah without any dissenting opinion.

Milchamos Hash-m: R. Chiya is refuted by the Beraisos supporting Rav and Shmuel. Therefore, even R. Meir permits male shafts.

Rambam (Hilchos Sukah 5:1): One may use for Sechach only something which grew from the ground, was uprooted, and is not Mekabel Tum'ah.

Rambam (2): If one used for Sechach Klei Etz or mats for sleeping it is Pasul, for they are Mekabel Tum'ah. If one used broken or worn out Kelim it is Pasul. Since they used to be Mekabel Tum'ah, we are concerned lest one use pieces that did not yet become Tahor.

Rambam (5): If one used male arrow shafts for Sechach it is Kosher. If one used female shafts it is Pasul. Even though they are made to be permanently filled with the iron (of the arrowhead), it is considered a receptacle and it is Mekabel Tum'ah.

R. Mano'ach: We discuss shafts that were never put in the arrowhead. If they were put in and the arrowhead came off, the shafts would be forbidden like worn out Kelim!

Question: Wooden Kelim without a receptacle are Mekabel Tum'ah mid'Rabanan. Even male shafts should be Pasul!

Answer (R. Mano'ach): The Sifri (Shemini 6:4) includes Kelim such as tables, which serve both man and Meshamshav (Kelim that serve man), like a sack. A ladder serves only man, and a candelabra (or arrow shaft) serves only Meshamshav, therefore they are not Mekabel Tum'ah even mid'Rabanan.

Rambam (Hilchos Kelim 2:3): A receptacle made to be permanently filled is not considered a receptacle and it is not Mekabel Tum'ah.

Teshuvas Rashba 1:195: If a ladder has holes to hold the rungs, this is a receptacle made for Melachah, just like female shafts. It is Mekabel Tum'ah mid'Oraisa. The Sifri says that a ladder is Tahor. It refers to a ladder without holes for the rungs, or a ladder used to carry loads (Ra'avad). The Rambam says that a receptacle made to be permanently filled is Tahor. It is not clear why this is unlike female shafts. Presumably he learns from the Mishnah (Kelim (17:17), which says that Tachtis of (iron) forgers is Tamei, but that of smiths is Tahor. He explains that the latter refers to a piece of wood with a receptacle for the anvil. However, R. Shimshon explains that it is a Keli put under the smith's feet. If it has a receptacle for scraps of metal it is Tamei.

Question (R. Akiva Eiger Kelim 13:6): Tosfos Yom Tov and Tosfos (Shabbos 52b DH Hi) say that a receptacle made to be permanently filled is not considered a receptacle and it is Tahor. What is their source? We conclude (Sukah 12b) that it is considered a receptacle!

R. Shimshon (Kelim 26b DH Tzeror): Rashi (Sanhedrin 68a DH Mahu) says that Chachamim Metaher a receptacle made to be permanently filled. This is wrong, for Sukah 12a considers it to be a receptacle. Also Tefilin are Mekabel Tum'ah (Kelim 18:8), even though the compartments are permanently filled.

Korban Nesan'el (1, on Rosh 1:24): The Rambam must explain that arrowheads are sometimes removed from female shafts. (The Gemara answered (Ka Mashma Lan) that female shafts are not considered a receptacle that is permanently filled, therefore they are Tamei and Pasul for Sechach.)

Chidushei ha'Ran (Bava Basra 66a DH l'Olam): Some Peshutei Klei Etz are Mekabel Tum'ah mid'Oraisa, e.g. those fit for Medras (to sit or lie on them). Some say that also Kelim that serve both man and Meshamshav are Mekabel Tum'ah mid'Oraisa. If they serve only Meshamshav their Tum'ah is mid'Rabanan. If they do not serve Meshamshav they are Tahor, like male shafts or mats made for Sechach. Others say that only Medras is mid'Oraisa. Even Kelim that serve man and Meshamshav are Tamei only mid'Rabanan.

POSKIM

Shulchan Aruch (OC 629:2): Anything that is Mekabel Tum'ah may not be used for Sechach, such as spits, bed boards or any Kelim. This is even if they broke and a Shi'ur for Tum'ah does not remain.

Source (Beis Yosef DH u'Mah she'Chosav): The Mishnah (15a) disqualifies these. Presumably it discusses Klei Etz, for metal is Pasul in any case because it did not grow from the ground.

Magen Avraham (1): Only metal spits are Pasul. Wooden spits are Kosher because they are Peshutei Klei Etz, just like male shafts! Indeed, the Mishnah (15a) is not a Chidush!

Mishnah Berurah (5): The Mishnah discusses wooden spits with iron tips, therefore they are Mekabel Tum'ah. One might have thought that they are Kosher for Sechach because the iron is not needed for the Sechach.

Kaf ha'Chayim (10): The spits are wooden, just like the bed boards. They are unlike male shafts, because the spits also serve Meshamshim, e.g. like a table.

Mishnah Berurah (6): Wood bed boards are Pasul for Sechach because they came from a Keli.

Shulchan Aruch (3): If one used for Sechach arrow shafts without a receptacle it is Kosher. If they have a receptacle it is Pasul.

Magen Avraham (2): The Rosh and others allow reeds even though there is a receptacle inside, because the receptacle was not made to hold anything. Orchos Chayim disagrees.

Mishnah Berurah (10): If a Klei Etz is slightly wide, one can rest things on it. It is Mekabel Tum'ah mid'Rabanan, for it resembles a receptacle, so it is Pasul for Sechach. Therefore, one should not put a shovel or rake on the Sechach, even if it is broken. In pressed circumstances Bechori Yakov is lenient about broken Kelim which were not Mekabel Tum'ah mid'Oraisa when they were intact.