Just finished a drawing for my latest delrin roller based carriage for a delta 3D printer.  This one uses hardware-free toothed belt clips.  You should be able to attach the belt with no tools or hardware.  Just wrap the belt, teeth toward the “teardrop”, such that the teeth mesh when the belt re-joins at the pointed end of the teardrop.  Insert this little teardrop shaped belt loop around the teardrop post, and it should hold tight.

Delrin wheel based carriage for Delta printer