I like watching them on YouTube. Dont the gears and rod wear out pretty quickly?
There is a rack, a pinon and the pinon shaft. I haven't heard anything about people wearing them out but I do run high pressure grease on the rack. It is all rather slow moving. Think of an arbor press on its back. The Chinese stuff was busting teeth and I don't know about the DR but the DR and the SS are very close to each other in cost at the end of the day.