My normal open-end wrenches are *too thick* to tighten! The shank under the built-in nut is wider than the nut itself, so when tightened it pushes the wrench against the base of the table leg! Doing the final turn of tightening with *thin* pliers worked fine, or if I had a thinner wrench that would be fine too. It was a little strange for a moment before I realized what had happened. In addition, they roll well, fluidly, fairly quietly (wooden floor) and are very good in all respects.