Many people have asked me this question. The 4-Shaft PVC Loom is a rising shed Jack Loom. Jack Looms typically hold the warp threads down approx. 1 inch below the imaginary line between the front and back beams. When one or more harnesses rise, this creates a fairly large shed perfect for weaving. For example . . .
Using the slider bars on the top of the loom, the jack “action” is smooth and fast making the weaving process quick and fun.