Parsha Mitzvot: Shelach- Ki Tavo: Noam Elimelech:Tzitzit

Is it true that one may not use scissors to trim the strings of Tzitzit, even before they are wound? U.S. It is true. The Kaf Hachaim (O”H 11: 17 & 39) compares the sanctity of Tzitzit to that of the stones of the Altar and Temple, about which the Torah teaches; (Deuteronomy 27:5) “You shall not raise iron on them.” He writes that it is better to use your 32 teeth, which correspond to the 32 strings, to trim them!
The Noam Elimelech (Noah) says that each generation has a “root” to repair one specific Mitzvah and that his generation should focus on Tzitzit.