The Gemara and Shulchan Aruch do not provide a precise definition of what is considered a hair and what is considered a shaved area. It seems that all would agree that one may trim the peyos, but exactly how close to the root each hair may be cut remains a point of dispute.
A. Without a Razor
The Rambam (Avoda Zara 12:6) rules that one is only prohibited from removing peyos with a razor. Cutting peyos off with a scissor that provides a cut as short as a razor is completely acceptable. The Darchei Teshuva (181:2) writes that the Sefer Hachinuch understands that while the Rambam exempts one who removes his peyos with scissors from a punishment, it is still prohibited to do so. However, a cursory glance at the Sefer Hachinuch seems to indicate that the Sefer Hachinuch only applied this stringency to shaving the beard, and not to shaving the peyos of the head. As such, the Rambam’s view seems very clear that one is permitted to remove his peyos using a scissor or a machine that cuts using scissor action. Tosafos (Nazir 41b s.v. Hashta) and the Rosh (Makos 3:2-3) disagree with the Rambam and maintain that the prohibition to remove the peyos ha’rosh would apply equally to removal with a razor and removal with any other cutting instrument. (see Beis Yosef Yoreh Deah 181 for an explanation of the dispute)
B. Halacha
While the Shulchan Aruch (181:3) rules in accordance with the Rambam, he then cites those who rule stringently in accordance with the Rosh and suggests concerning ourselves with the more stringent view. (See Darchei Teshuva 181:2 who rules that one who unwittingly followed the ruling of the Rambam need not repent for his sin, as the Shulchan Aruch rules that the strict halacha is in accordance with this view.) It therefore seems that one should not remove his peyos, even if he plans on doing so with a scissor type of instrument (most hair trimmers would probably have the halachic status of a scissor). However, the exact length that the peyos hairs may be cut to still remains unclear. The poskim have looked for clues throughout rabbinic literature for the definition of a significant piece of hair:
- The Rambam (Nezirus 5:11) writes that a nazir is only held accountable for cutting hair in a way that he removes it entirely. If he trims his hair and leaves the length that would allow the top of the hair to be bent back toward its root he is said to have left hair and is therefore not punished for shaving his hair. Dayan Yitzchak Weiss (Minchas Yitzchak IV:113:5) applies this same criteria to the length of hairs in the peyos. Rav Yisroel Belsky suggests that when one uses a number two extension on a trimmer he has left a substantial enough length of hair.
- The Rambam (Hilchos Parah Adumah 1:4) rules that a completely red cow that has two white or black hairs would not have the status of a Parah Adumah. If however, the hairs are so short that one would not be able to grab them with tweezers the hair is considered to not be there at all. Apparently the Rambam has another definition of a significant amount of hair, namely that which can be grabbed with tweezers. If this were applied to the halacha of peyos it would constitute a considerable leniency and would even allow a person to get a “number 1” haircut on his peyos. Indeed, Rabbi Herschel Schachter cites the opinion of Rabbi Moshe Soloveitchik that as long as the hair is long enough to “scratch with a fingernail” it is not considered to have been destroyed (Nefesh HaRav page 234).
- The Biur Halacha (251 s.v. Afilu) writes that one cannot cut his peyos to the point that they are “literally close to the skin” but can leave “very very little”. While the Biur Halacha does not quantify what is considered “very very little” one may suggest that the intention is for even the shortest hairs so long as their presence is easily felt. (See Perisha 181 who also implies that very short hairs are acceptable).
