⚖️ Daily Halacha: Cutting nails when Rosh Chodesh falls on Erev Shabbos; Shabbos Rosh Chodesh

May one cut his nail when Rosh Chodesh falls on Erev Shabbos?^[1]

When Rosh Chodesh falls on Erev Shabbos, some Poskim^[2] rule it is permitted to cut the nails on Erev Shabbos Rosh Chodesh, and so is the implied opinion of Admur. Other Poskim^[3], however, rule one may not cut the nails on Rosh Chodesh even when it falls on Erev Shabbos. [Practically, one who cuts his nails on every Erev Shabbos may be lenient to do so also on Erev Shabbos Rosh Chodesh.^[4] Likewise, one with very long nails may be lenient to cut them.^[5] However, some Poskim^[6] conclude that initially it is proper to cut the nails on Thursday, or Wednesday if Rosh Chodesh falls on Thursday-Friday, and hence avoid entering the dispute.]

Shabbos Rosh Chodesh:

• When Rosh Chodesh falls on Shabbos one Davens the regular Shabbos Shemoneh Esrei, which contains seven blessings, for Maariv, Shacharis and Mincha, adding Ya’aleh Veyavo in the blessing of Avoda. The regular dialect of Ya’aleh Veyavo is recited without adding the day of Shabbos to its wording.
• When Rosh Chodesh falls on Shabbos one adds in the fourth/middle blessing of Shemoneh Esrei the paragraph of Ata Yatzarta which discusses both [the sacrifices of] Shabbos and Rosh Chodesh. One concludes the blessing “Mikadeish Hashabbos Yisrael Veroshei Chodashim”.
• Kerias Hatorah-The Torah reading: When Rosh Chodesh coincides with Shabbos two Sifrei Torah are removed from the Ark. Seven Aliyos from the weekly Torah portion is read from the first Torah scroll. The second scroll is then placed on the Bima which is followed by half Kaddish. Hagba is then done to the first scroll. One may not open the second scroll until the first scroll is rolled up and placed in its Meil. [The Mi Shebeirach for the ill is recited after Hagba.] The Maftir, which is the Rosh Chodesh reading, is read from the second Torah scroll. One reads the portions of “Uviyom Hashabas” and “Uviroshei Chodsheichem” until the end of that portion. One does not recite a second half Kaddish after this reading.
• Haftorah: When Rosh Chodesh falls on Shabbos the Haftorah of “Hashamayim Kisi” is read.
• If Shabbos is Erev Rosh Chodesh then the Haftorah of “Machar Chodesh” is read in place of the weekly Haftorah. 
• When Rosh Chodesh is two days and falls on Shabbos and Sunday then the Haftorah of “Hashamayim Kisi” is read and after the Haftorah one reads the first and last verse of the Haftorah of “Machar Chodesh”.
• Shnayim Mikra: When Rosh Chodesh falls on Shabbos one is not required to read the verses of the Rosh Chodesh reading as part of Shnayim Mikra. However, one is to read both the Haftorah of the weekly Parsha and the Haftorah which will be read in Shul. Accordingly, if Rosh Chodesh is two days and falls on Shabbos and Sunday, one is to read three Haftoras; the weekly Parsha, the Haftorah of Hashamayim Kisi and the Haftorah of Machar Chodesh.
• Av Harachamim: Av Harachamim is not recited on Shabbos Rosh Chodesh. This applies even on Shabbos Rosh Chodesh Iyar.
• Tzidkasecha: When Rosh Chodesh falls on Shabbos, Tzidkasecha is not recited during the Mincha prayer.

[1] See Piskeiy Teshuvos 260:10; Sefer Shemiras Haguf Vihanefesh [Lerner] 68:6 footnote 6

[2] Tehila Ledavid 260:1; Shaar Hakolel in Nesiv Hachaim 48:3; Shivim Temarim 57 as is the simple implication of the Kneses Hagedola ibid, Beir Heiytiv ibid, Elya Raba ibid, M”A ibid, and Admur ibid who all omit the custom to avoid cutting nails when mentioning the custom to avoid cutting hair on Erev Shabbos Rosh Chodesh [However, see Ketzos Hashulchan 72 footnote 4 who leaves the opinion of Admur on this matter in question.]; Opinions brought in footnotes on the Tzavah ibid; See Minchas Shabbos 72:66; Alef Hamagen 12; Maharam Brisk 2:99; Meishiv Halacha 2:4; Kitzur Hilchos Shabbos-Supplements

The reason: The reason some have the custom not to cut their hair on Rosh Chodesh even when it falls on Erev Shabbos, despite the fact that it is a Mitzvah to get a haircut on Erev Shabbos, is because one is not obligated to cut his hair every Erev Shabbos. However, being it is a Mitzvah to cut the nails on every Erev Shabbos [see wording of Admur ibid], one is allowed to cut his nails even on Erev Shabbos Rosh Chodesh, as one who fulfills a Mitzvah will know no harm.  It thus seems that no such custom exists against cutting the nails on Erev Shabbos Rosh Chodesh and they should therefore be cut in honor of Shabbos. [Shivim Temarim ibid]

[3] Derech Hachaim Dinei Erev Shabbos; Ashel Avraham Butchach Tinyana 417; Mili Dechassidusa 57; Kitzur SHU”A 72:14; Aruch Hashulchan 260:6; M”B 260:7 “There are communities who do not cut their hair or nails on Rosh Chodesh even when it falls on Shabbos”; Likkutei Maharich “It is difficult to do an action against the great Poskim”; Kaf Hachaim 260:12 allows only cutting the nails that stretch past the skin; Piskeiy Teshuvos 260:10 “Initially one is certainly to suspect for the ruling of these Poskim”; See Shaareiy Teshuvah 260:1 in name of Machazik Bracha 260; Ketzos Hashulchan 72 footnote 4 leaves this matter in question

[4] Shivim Temarim ibid; Orchos Chaim Spinka 260:3 in name of Alef Hamagen 12 and Piskeiy Teshuvos ibid that if one forgot to cut them on Thursday/Wednesday, one may cut them on Erev Shabbos in such a case even if he only cuts his nails every other Shabbos; Vetzaruch Iyun if the lenient Poskim above [i.e. Nesiv Hachaim, Tehila Ledavid] agree with this and limit their allowance only to one who is always particular to cut his nails on Erev Shabbos, as on the other hand their reason of Shomer Mitzvah should apply in all cases. On the other hand, if so, then even haircuts should be allowed. Vetzaruch Iyun. 

[5] Mili Dechassidusa ibid; Kaf Hachaim ibid; Piskeiy Teshuvos ibid

[6] Shivim Temarim ibid “In my opinion, if one forgot or could not cut his nails before Friday…..In my opinion, one is to initially cut it on Thursday and not Wednesday in order so it be as apparent as possible that he is doing so Lekavod Shabbos…There is no need to worry in such a case to those who are particular to not cut them on Thursday.”; Shaareiy Teshuvah 251 and 260:1 in name of Machazik Bracha 260:6; Ashel Avraham Butchach Tinyana 417; Mili Dechassidusa 57; Darkei Chaim Veshalom 394; Az Nidbaru 12:4; Piskeiy Teshuvos 260:10; Vetzaruch Iyun if the lenient Poskim above [i.e. Nesiv Hachaim, Tehila Ledavid] agree with this and rule that initially one should cut it before Erev Shabbos.; Sefer Shemiras Haguf Vihanefesh [Lerner] 68:6