in which he teaches that "Torah is his craft" refers to those who study during the entire time when they are not engaged in their craft
To whom does "Torah is their craft" refer? To those who engage minimally in a craft or commerce for their livelihood and review Torah or study on a regular basis, whenever they have a free moment … A Torah scholar for whom "Torah is his craft" returns to his studying at every opportunity that he is freed from his dealings. There have been Torah scholars who have a shop and spend most of their day dealing in commerce, sitting in their shop all day, such as the one in Bzazin.
Mishpatim Yesharim, p. 81b, question 172, Cracow 1891, Jerusalem 1993, second printing