Keilim 27:6-7

Keilim 27:6

The following things are measured when they’re doubled over: socks, pants, undergarments, a cap and a money belt. A patch sewn onto one’s hem is measured flat if it was sewn on flat (i.e., on one side) doubled if it was sewn on doubled (on both sides).

Keilim 27:7

Let’s say that a piece of cloth of which one has woven three handbreadths by three handbreadths contracts midras impurity and he then completes the garment. If one then removes one thread from the original part, the garment is purified of midras impurity (the part that was rendered impure having been reduced in size) but it remains unclean from contact with midras impurity. If he removed a thread from the original part and only subsequently completed the garment, the garment is impure from contact with midras.