I will do a little more searching to see what I can find for the rack and pinnion and come up with some sort of design unless zany one knows of something avalable for mod 1 rack? Many thanks[/QUOTE]

Hi, first of all let me say that I am a machine user(converter) and have never built a machine. I think that your giant will be awesome for the uses you plan. With regards to tensioning the R&P, I think the most simple way would be to pivot the drive and have an extended arm with an adjustable slide weight to let gravity do the tensioning. Perhaps this is just too easy, I'm sure I will soon hear why its a stupid idea, but I do love simplicity!!! G.