Hi Windy,
the gear motors are from Pololu at 1:35 gear reduction:
http://www.pololu.com/catalog/product/1091
and the electronics is RB-45 from Electron retracts. I put a couple of "O" rings at each end stops in the threaded rod and any issues. The thread rod is made of F-210 (foral steel)
and the pin from brass.
Jesus A.Serrano