What are "Chatzeros Keturos"?
Rashi citing Midos 2:5: They did not have a roof. (Radak ? this is why they are called Chatzeros. Malbim ? the Kitor (smoke) goes up (there is no roof to stop it).) The Mishnah explains their functions (refer to 46:21:3:1).
Radak: This is like Keshuros. The Targum of "va'Tikshor" (Bereishis 38:28) is u'Ktaras. They are connected in the corners of the Chatzer and tied to them. This is like "va'Tikasher Kol ha'Chomah" (Nechemyah 3:38). However, the Mishnah explains that they did not have a roof (refer to 46:22:1:1).
The chambers will be 30 wide. What do we infer from this?
Radak: Also Bayis Sheni was like this. The Mishnah (Midos 2:5) said only 40, i.e. the length; it did not give the width.
Malbim: The width was from north to south. If it were from east to west, and the length (40) from north to south, there would not be room for Lishkos ha'Me'ah, based on what I explained above (42:1).
What is the meaning of "Mehuktza'os"?
Rashi: The corners of the Chatzer.
Radak: This is Hif'il conjugation, from Hiktzi'a; they have corners. There are dots on the word; there are 15 such words in Tanach.
