Melacha #31 – M’chateich (Cutting to size)
The hides were scored to enable them to be cut to pre-measured sizes. This is the melacha of m’chateich. (M’chateich is more than just cutting; it specifically refers to cutting to pre-determined sizes and shapes.)
M’chateich applies to virtually all substances except food. One need not use a knife or scissors to cut; m’chateich can also be accomplishing by tearing something to size with one’s bare hands. Examples of m’chateich can include opening a box of tissues or separating paper towels along the perforations. If one must tear bathroom tissue on Shabbos, he should do so in the middle of the sheet rather than on the perforations. In this way, a person avoids issues of m’chateich.
However, if a perforation is not intended to create a neat, measured cut but only to facilitate opening a package, the item may be opened in the normal manner. Nobody cares if a packet of sugar or a bag of potato chips has a neat, measured opening. If it should happen to tear cleanly across a perforation, so be it. The person opening the package has no interest in the measured piece that results from his actions; such an outcome is both unintended and of no particular benefit.
This is just an introduction to the concepts of the melacha of m’chateich; it is not a substitute for a full study of the halachos.