This model adds an additional segment to the middle of the Open Lathe's bed, adding an additional 200mm of bed length. This must be added during the initial build of the lathe! Print one of each component in addition to the original Open Lathe components and assemble per the original instructions. For the concrete pour, I was able to use standard high strength concrete with no sieving, and strongly recommend some way to vibrate the lathe during the pour. I ended up holding a reciprocating saw with no blade against the thabe the lathe was on during the pour.