In our maker space, we have a CNC router table rebuild going on that uses the Avid motor drive and a R&P setup. One of the members wants to mount the rack with the teeth pointing up so that he can use gravity to hold the pinion against the rack. He claims that mounting the rack with the teeth pointing down and using a spring to hold the pinion against the rack will cause premature wearing of the spring. Anyone ever seen the spring wear out and need to be replaced?