Hi Rich, My build of the 3DR is about 90% complete.( All parts were done on my first Mendel printer) I would like to show you my design for retaining the LU bearings to the Carriages, rather than using the tie wraps. Please find enc. two pics, consisting of the spring clip and a pic. of the carriage and spring clip assy. The spring clip utilizes the existing holes that were used for the tie wrapsby Terence Peake - RepRap magazine