These clamps are great for a medium-scale woodworking project (in our case a table).  They are a snap to install on the pipes purchased from the local big box store.  The only difficult part was screwing on the retaining rings.  I tore my fingers up a bit getting those on the pipe.  Otherwise, these clamps do exactly what we need them to do.  The screw mechanism is smooth and fluid and the sliding clamps work perfectly.