Reed Space.
The reed space of a loom is measured from backboard on the one side to the fork grate on the other. Thus, what is called a 40-inch loom measures 45 inches reed space, and in it it is usual to weave cloth up to 41 inches wide, although it is possible to weave 42-1/4-inch cloth in it. A 26-inch loom has a 30-inch reed space, and will weave to 28 inches. In wider looms the reed space is about six inches above the nominal size of the loom.