Don't Have A Ribber? Here's Why You Should Consider Buying The Clamps - The ribber clamp is sold with the ribber, however, if you don't own a ribber, you may find that having your machine up at an angle makes knitting, especially lace knitting, easier. The knitting naturally slips down the needles toward the needle bed due to gravity. The tendency for the knitting to slide forward as the needle moves forward is minimized. So there is less chance of the stitches dropping off. The weights are more effective as well. A ribber clamp set is a good investment for non-ribber owners.