eishes chayil:
I have repeated this here and other threads on this subject. There is a place for a potch. However, the determination of when it is appropriate is more complex than it ever was. Instead of attempting to mimic what he know or hear about of past generations, we need to see what the gedolim of our times tell us of the guidelines.
Earlier, there was quote about the Brisker Rov. Let’s see what he stated. I report this from a verbatim quote published in a reputable seferon chinuch. The Rov said that the first potch might be permissible under a list of conditions. The second potch is an issur min haTorah of assault. The Gemora instructs this potch to not be with a strap but with a shoelace. It is clear that the potch is not there to punish but to teach. If we cause pain to a child or talmid, are we teaching, or are we establishing the fear to force compliance. The latter might help control the classroom, but it is dishonest to call that teaching.
With all the opinions here, I still ignore all of them, in total deference to the guidance from so many Gedolim of the current and recent generations. The material from their guidance is accessible. We cannot expect a positive result from running our homes and yeshivos like a boot camp. Teach them. Model for them. It works.