Recently I received an inquiry from a Jew in Istanbul asking about the rabbinical supervision on the tallit katan and tzitzit products we sell.
Which rabbinical authority are you supervised by? For example, when you buy a mezuzah or a pair of tefillin,
don’t you make sure first that the sofer is a trusted individual and has credibility for his work???
They are made by Mishkan Hatchelet, which has a hechsher by the Eda Charedit of Jerusalem. The tzitzit strings are under the supervision of the Eda Charedit, HaRav A.A. Wosner or the Zichron Meir Beit Din, depending on which thickness you choose. The tzitzit tie-ers we use are almost all ultra-Orthodox, but really the halacha only requires they are tied by a Jew, with the mitzvah of tzitzit in mind, and not on Shabbat. With a sofer it’s a very different story, and you really do need someone you trust implicitly. It’s a bit complicated to explain why, but in a word because a mezuzah, tefillin or Sefer Torah has a much higher level of kedusha, and because there are things that could happen that would render it halachically invalid and nobody besides the sofer would ever be able to know.
The truth is that strictly speaking, rabbinical supervision is not a necessity. What exactly needs to be verified? If you have a reason to suspect shatnez, you will want to know that a rabbi made sure there is no shatnez. (Our seamstress once told me she thought the atara a customer had asked us to sew onto a wool tallit was made of linen. I looked into the matter, but it turned out that the manufacturer does not use linen.)
When it comes to handmade and handwoven tallitot (i.e. tallit gadol), generally there is no rabbinical supervision. One of the most common halachic problems I have come across is that the holes for the tzitzit are not located in the correct place. If they are too close or too far from the edge, it is a real problem. (If you can read Hebrew, Mishkan Hatchelet describes the correct tzitzit positioning.)
In the case of tallit katan garments, usually the tzitzit holes are positioned properly and the real thing to look out for is the part that goes over the shoulders. A tallit katan has to have more cloth than airspace. What does that mean? Imagine you lay a tallit katan flat on a table and look down at it. Let’s say you measure the width at the shoulders and find that the hole for the head is 30 cm wide and there is 14 cm of cloth on either side. That means you have more air than material ( since 30 > 28). This problem is fairly common with cotton tallit katan garments.