Miksheh Achas Battim
Question: I’ve heard there are two types of battim: “Miksheh achas” battim which are more expensive, and “regular” battim which are less expensive. What’s the difference between them, and which ones are preferrable?
Discussion: Every pair of battim in the world is comprised of multiple elements. Two of them are the tittura elyonah (upper base) and the tittura tachtonah (lower base). Together they comprise the base of the tefillin. The tittura tachtonah is folded under the tittura elyonah, and they are then sewn together to seal the tefillin (illustrations 3 and 4).
When working on this stage of the battim-making process, it is often difficult for the battim macher to align the two titturas. Adding a filler between them often makes the battim more stable and secure.
Miksheh achas battim (battim from one piece), as their name implies, are created from one unit without any filler. Most Poskim agree88 that there is no hiddur in miksheh achas battim; Rav Elyashiv has even been quoted as saying there is no reason to spend extra money to buy them.89
With that said, often those who produce miksheh achas battim are keeping to an overall higher standard. That may be a reason to prefer such battim. One needs to do one’s homework and examine each case to determine whether it is worth the extra money for him.
88 R’ Chaim Kanievsky writes in Da’as Notah III:537-538 that it is a hiddur to purchase miksheh achas battim specifically; cf. footnote 734 ad loc. where the editors struggle to explain this position and bring a conflicting answer from him to a different questioner. Furthermore, it is clear in Levush 32:44, quoted by Beiur Halachah 32:37, ד"ה עור הבתים , that standard battim are not miksheh achas.
89 When asked whether there is a source to only purchase miksheh achas battim, he famously replied, “The only source for miksheh achas is regarding the menorah” (Shemos 25:31).
Some Acharonim, though did prefer battim that are mikshah achas; see Stam Kehilchasan, pg. 9, written by R’ Moshe Sternbuch and Hidurei Tefillin 1:3 written by R’ Sraya Deblitzky.