fits M5 Jam Nuts to 20mm V Slot extrusion Added V2, not sure if this is an improvement or not. Concept was for a small amount of plastic to act as a washer to help spread the nut force onto the extrusion. Will also help print easier. Update: definitely print the V2 version. The washer effect helps. Due to the V of the extrusion, over tightening the bolt can cause shear failure (as opposed to bending) of the extrusion edge... Also don't over tighten ;)I recommend 0.2 layer height and a 0.4mm or finer nozzle. A 0.5mm nozzle may work but I haven't tried. The skinny side strips are critical to prevent the nut from turning. If they break the nut will spin.