Hello All, I have just registered with the site and this is the first time posting. I'm also fairly new at machining, so please forgive my ignorance. I just purchased a Leblond 15x30 servo shift. Basically from a friend of a friend and has been sitting for a while. It was his fathers and said it worked fine when they disconnected power. I have read the manuals and watched videos on how it operates. The question I have is, it has an extra knob on the front of the plate. It seems to lock in and out of gear. I do not have lathe under power yet. But would like to know how this will fit into the operation before i hurt anything. I have read different places about a conversion to manual. Not sure if this is it or not. If i can figure out how to post a picture i will. Thanks in advance.